"Elizabeth... the kingdom's top priority is to ensure your safety. But that's got nothing to do with me. Whether you live or die... is like a grain of sand in the path to the Holy Knights' rule. Leave. I only have business with the Sins."
Gilthunder is a relatively tall young man with slightly curled, short salmon-colored hair. He has thin eyebrows and a pair of blue eyes.
He is seen wearing dark-colored full body knight armor without a helmet and wields a single hand sword. The upper body armor is carved with several crosses and the symbol of the Holy Knights. He also has a leather waist belt fastened on top of his armor.
Gilthunder was a seemingly cold and cruel individual around the start of the story, devastating a town by stopping its source of income just because he was angry at them. When he learned that a child pulled out his sword, he threw a spear at the town just to check whether it wasn't an accident, even though the town could have been destroyed. However, despite that, he is honorable as he gave Meliodas a final request when he thought that he was dying. He has a desire to kill the Seven Deadly Sins for apparently killing his father and to prove by killing them all that he has surpassed his father.
In his childhood, Gilthunder was sweet and friendly especially towards the Seven Deadly Sins, specifically Meliodas, who trained him in the art of swordsmanship before turning dark after the Seven Deadly Sins were accused of killing his father. However, it was revealed that Gilthunder was acting cruel and ruthless as Margaret, the woman he loves, was being held hostage by a monster close to her, and that he must join the Holy Knight plan, no matter what. After being freed by Meliodas, Gilthunder returned to his old and kinder self.
Back in the old days, Gilthunder was friends with Howzer, Veronica Liones, and Elizabeth Liones and used to play together. At some point of time, Meliodas taught Gilthunder the fundamentals of swordsmanship and "The Way of the Knight". Gilthunder used to look up to the Seven Deadly Sins and wanted to be just like them. During one point, Gilthunder became Margaret Liones' personal knight and had a crush on her during their childhood. During one of his training with Meliodas, Gilthunder grew upset as he believed he would never become as strong as the Deadly Sins or his father, but Meliodas told him to ditch his negative attitude and Margaret came, and told him The Way of the Knight creed. Margaret told Gilthunder that he should be himself, and not like the Deadly Sins or his father, and she believes that Gilthunder will be the kindest and strongest Holy Knight some day which cheers up Gilthunder. However, the next day Gilthunder came running toward Meliodas and told him to run away with the others. Meliodas was lost at Gilthunder and told him to explain everything, but Gilthunder told him something terrible is coming and if he told somebody, bad things will happen, and Gilthunder had no idea what to do.
Meliodas told Gilthunder to calm down by hitting his head and asking him what he wants to do, which Gilthunder said that he needed to protect Margaret, but had no idea how to do it. Meliodas taught him a charm which could cheer him up whenever he feels sad or terrible which was to say out loud that he was stronger than any of the Seven Deadly Sins. Gilthunder said it, which Meliodas points out that he should feel better soon. Meliodas embraced Gilthunder, told him he shouldn't cry, and if he is in trouble, he will come to his aid. Ten years later, Gilthunder was forced to join with the Holy Knights for Margaret's safety and somehow knew of his father's true murderer.
A day before Meliodas, Hawk and Elizabeth arrived at Bernia, Gilthunder had gone then to collect the taxes, and while doing so, had drank the very popular Bernia Ale. Even though it was the best ale Bernia had to offer, the Holy Knight insulted it and called it "only slightly better than a horse's urine". Mead, angered by this comment, dropped a bug in his next drink, which angered Gilthunder, who, in his anger, sealed the underground water source of the river in Bernia with a sword imbued with his lightning magic. That prevented the villagers from making the ale, which is the sole economic income for the whole village.
He was residing in and governing Fort Solgales when he was informed of a child having pulled his sword, and he, deciding to confirm whether this was an accident or not himself, borrowed a spear from one of the guards and threw it directly at Bernia. Meliodas, however, stopped the spear and threw it back, which resulted in the fort's destruction, and Gilthunder's realization that the Seven Deadly Sins were still alive.
Upon arriving in the Forest of White Dreams by using a gigantic thundercloud and a lightning bolt, Gilthunder immediately immobilizes everyone with his lightning magic. As Meliodas and Diane realize that he is a Holy Knight, Elizabeth recognizes him as Gilthunder, a Holy Knight very close to her father, and a brother figure to her, and initially doesn't believe that he was the Holy Knight who had dammed Bernia's water source, and is greatly surprised when she realizes that he was the one. Gilthunder, informing her that while her safety was the kingdom's priority, she was only a "grain of sand in the path to the Holy Knights' rule", and after releasing her, orders her to leave. She, however, refuses to do so or let him hard Meliodas and Diane, and when Gilthunder kicks a weakened Hawk out of the way, runs towards him.
Gilthunder, points his sword at Meliodas' neck, stating that he wants to avenge his father, the deceased Great Holy Knight, Zaratras, and also wants to prove that he has surpassed him, leading Meliodas to recognize him as "Little Gil", Zaratras' son who would often follow the Seven Deadly Sins. Gilthunder then also declares that he is now stronger than any of the Deadly Sins, and offers to unbind the two to fight, but before he could do so, however, they easily break his spell themselves, with Meliodas instructing Diane not to interfere in their battle. As Gilthunder then attacks first using a powerful lighting bolt, the Sin of Wrath easily repels the spell back at Gilthunder, but the latter dodges the attack and moves behind the former, slashing him from behind and causing him to collapse.
Meliodas, seemingly in his last moments, is question by Gilthunder for any last questions, with him asking for the whereabouts of the other five Deadly Sins. Gilthunder answers, telling him that while the whereabouts of three of them remain unknown, it is known that the Fox's Sin of Greed is imprisoned in the Baste Dungeon and the Grizzly's Sin of Sloth has perished in the Capital of the Dead. Hearing that, Meliodas quickly jumps back up, leading Gilthunder to realize that Meliodas let himself be gravely injured in order to obtain the information. He then proceeds to repeatedly attack him, only for Meliodas to dodge all his attacks. The Holy Knight eventually moves behind Meliodas again and points his sword towards his neck. Diane then suddenly interrupts the battle, lifts him with her hand, and despite his attempts to escape her grasp by discharging lightning, throws him from the forest.
Gilthunder is later seen falling down from the sky into a church in a neighboring village. He walks out unscathed from the remnants of the collapsed church, whilst the priests and civilians cry for help.
In the village that is also the entrance to the Capital of the Dead, Gilthunder informs King, who had formed an alliance with the Holy Knights to kill Ban, about Fort Solgales' and Baste Dungeon's destruction, the Weird Fangs' annihilation, and Ban joining Meliodas and Diane. He also warns King to not betray his trust, to which King asks him to keep things such as trust between humans and that his way was more convenient for both of them. Oslo, being as small as an ordinary dog due to not being threatened at all, then enters the room, and informs King about having found his target. King, showing Gilthunder the badges of Andre and his partner, who had been killed earlier by Oslo, then asks the Holy Knight to order his subordinates to not get in his way, lest he shall kill them along with his intended target, Ban.
Gilthunder, along with a colleague, Howzer, is later ordered to confront and stop the invasion of the Northern Barbarians' army, which, numbering three thousand, had annihilated many knights. The two arrive on the battlefield on a flying dragon, and after landing on a lightning bolt created by Gilthunder, quickly defeat the entire army with ease. After returning to the castle, the Great Holy Knight, Dreyfus, commends them for their work, and after, Howzer questions him if that "errand" wasn't the predicted Holy War, assures him that it wasn't. Gilthunder then expresses his suspicions of their foe, who has not been predicted, being the Seven Deadly Sins, since four of them had already reunited.
After a small discussion on their captain, Meliodas', abilities, Dreyfus mentions the "New Generations" of Holy Knights, with Gilthunder then reporting to Dreyfus about many Holy Knight apprentices, many of whom were considered failures, suddenly and mysteriously gaining incredibly strength, and that he senses someone of something to be the phenomenon's source. After Howzer leaves, Gilthunder goes closer to Dreyfus and informs him silently that the second Great Holy Knight, Hendrickson's, subordinates have been calling for several apprentices.
When Howzer came back from Vaizel, Gilthunder reported told him that Veronica and Griamore were killed during the Vaizel event. Howzer ask how they doing to report all this to princess Margaret and Great Holy Knight Dreyfus, Gilthunder told Howzer that Dreyfus lock himself in his private room. Gilthunder look outside and said that things are going amiss and that Hendrickson group of Holy Knights has grown dramatically, and they were all New Generation, even stating in the past that Hendrickson and Dreyfus were even in powers but the balance is being broken by Hendrickson and wonder if this was another precursor of the Holy War.
Gilthunder wore his normal clothes and visited the first princess, Margaret Liones, to report Veronica's death. Once Gilthunder told Margaret of her sister's death, the latter grew anger at Gilthunder, believing that the Holy Knights were the one who killed her sister. Gilthunder told Margaret that it was the Seven Deadly Sins to which the latter refuse to believe since her father formed the group and the Holy Knights are the true traitors and cursed Gilthunder for working for them. Gilthunder was ordered by Dreyfus and Helbram to stop the Deadly Sins from attacking Liones along with Howzer, Guila, and Jericho. As they walk into Merlin's old castle, Howzer asks Gilthunder if Meliodas taught him how to use a sword but Gilthunder responded that he taught him the fundamentals of the sword. Howzer asked if Gilthunder could fight someone he used to look up to which Gilthunder respond that the Deadly Sins are the criminals while the Holy Knights are the ones who should stop them. The Holy Knights then sense a sound coming from downstairs which they went and found Diane stuck.
Gilthunder went closer to Diane, telling her that the Giants are dense beings since Diane is unaware how much trouble she is in now, but Jericho rushed in and tried to slay Diane who smashed her with her hammer, Gideon. Gilthunder ended up saving Jericho, who explained how powerful the Deadly Sins are with their Sacred Treasures. Gilthunder used his power, Thunder Bolt where he injured Diane as Howzer was forced to fight back and used Tempest which their combined their power created Dragon Castle and sent Diane flying. Diane manged to break free from Dragon Castle and landed back on her feet. Gilthunder witnessed his uncle Dreyfus' use of Break on the Deadly Sin and easily defeated her, sending the giant flying to the populated area of Liones. He soon accompanied his uncle and Howzer as they approached Guila, Helbram and Jericho who were near an incapacitated Diane. Gilthunder soon witnessed his old partner's and Guila's defection when the two rushed to protect Diane, who had their reasons to turn against the Holy Knights. Gilthunder remained silent during the conversation of Dreyfus, Helbram and Jericho trying to convince Howzer and Guila to come back to their side. After his uncle branded the two traitors, Gilthunder readies his weapon to battle his now-former partner and was seemingly caught by Howzer's Rising Tornado and bombarded by Guila's Shot Bomb in a form of a Combined Technique: Bomb Cyclone.
As the two rogue Holy Knights continue their assault, Gilthunder was revealed that he had not been caught by Howzer's twister all this time and attempted to strike Guila from behind with his lightning-infused sword, only to be blocked by Howzer. This, however, cancels their combined technique and frees Gilthunder's comrades in the process. Still locking weapons against each other, Gilthunder witnessed Guila being saved by Gowther from Dreyfus' Pierce and displayed no emotion when the Goat's Sin of Lust revealed his true identity to the Holy Knights at all. He later witnessed his uncle stabbing through Gowther and later both combatants then froze. When Dreyfus freed himself and collapsed due to mental injury, Gilthunder abandoned his battle with Howzer and helped his uncle to safety. Some time later, he and Dreyfus witnessed Helbram in his true form as a Fairy and full display of his power over the Sacred Tree.
While Meliodas and Hendrickson were battling against each other, Gilthunder came down from a thunder cloud and attacked Meliodas, who was able to parry his attack. Both exchanged multiple attacks, and both blocking each one of them, but eventually Gilthunder was able to kick Meliodas in the chest and send him back, where he was caught by Arthur. Gilthunder and Hendrickson decided to work together to fight off against Meliodas and the king of Camelot, Arthur Pendragon. After Hendrickson insulted Meliodas for his efforts to rescue the princess, Gilthunder and Hendrickson received a full double brunt attack from the Dragon's Sin of Wrath, receiving minor slashes on their faces as they're being taunted to try to stop him then. Gilthunder started to battle with Meliodas, while Arthur fought with Hendrickson. Gilthunder started to overwhelm Meliodas with great speed and when Gilthunder was about to finish off Meliodas, Meliodas stopped his attack with just his fingers and was in his Black Mark mode. Once Meliodas stopped Gilthunder's attack, he regained his sword back and went on with the fight, without the Black Mark.
Meliodas and Gilthunder's battle rages on and shows that both of them are equally matched. Gilthunder sent Meliodas flying to a building, but Meliodas stops the crash by putting his feet inside the building. Meliodas asks Gilthunder if he really wants to have a death match with him, which Gilthunder responds by using Meliodas' old creed of The Way Of The Knight which the creed goes "your eyes are to discern evil, your mouth to speak the truth, your heart is filled with righteousness, and your sword is to purge evil" but Gilthunder now believes that the Deadly Sins have turned down that creed and betrayed the kingdom. Gilthunder claims that he is stronger than any of the Deadly Sins, but Meliodas just nodded and continued on their fight with full speed. Later on, Meliodas started to overpower Gilthunder, while the latter tried to fight back with all his strength, but with no luck. Meliodas tries to slice Gilthunder, but Hendrickson appeared and struck Meliodas which the latter dodged in time, Meliodas was surprised to see Hendrickson and saw Arthur was defeated. Gilthunder and Hendrickson decided to team up in order to defeat Meliodas, as he was their greatest threat. The Unnamed Holy Knight appears and helps the duo do battle against Meliodas.
As the trio starts to overpower Meliodas and knock him next to a building, Vivian, amused that Meliodas was mortally wounded, as he had not used Full Counter or his Demon powers, but Gilthunder sensed that Meliodas power was increasing instead of decreasing. Hendrickson said that they have miscalculated and knew where the eerie premonition came from. Hendrickson found out that the reason for Meliodas not fighting back is because Meliodas is heightening his utmost power and senses to unleash a one decisive attack. The Holy Knights combine all of their power together in an attempt to finish off Meliodas before he can unleash his attack. Hendrickson summons Hellblaze, Gilthunder uses Sword of the Thunder Emperor, and Vivian unleashes Quad-Element Destroyer as Meliodas summon his attack, Divine Slayer. However, Margaret comes running toward the battlefield to stop Gilthunder from hurting his hero, Meliodas. However, Meliodas, spotting something next to Margaret, unleashes his Divine Slayer to kill an invisible demon. Pleased with destroying the creature and with no time to dodge, Meliodas takes on the full force of Vivian's attack, leaving him heavily injured. Seeing this opportunity, Hendrickson rushes towards Meliodas to finish him off but is instead repulsed and has his arm cut off by Gilthunder. Gilthunder, with a tear in his eye, smiles and thanks Meliodas for setting him free from his curse.
As Gilthunder cuts off Hendrickson's arm, Hendrickson yells out in anger at the sudden betrayal. However, Gilthunder points out that he was never on his side to begin with. As Hendrickson tries to summon Hellblaze with his left arm, Gilthunder stops Hendrickson and sends him flying. Gilthunder asked Meliodas to leave it to him, as he was waiting for this moment for a long time to have his revenge against his father's murderer. After the long battle, Gilthunder stabbed Hendrickson and unleashed his full power of his Thunderbolt and defeated him. He then reunited with Margaret and joined Meliodas and his company who came after the battle along with Gilthunder's Holy Knight friends (Howzer, Guila, Jericho, and Dreyfus) to rescue Elizabeth. While heading to the castle, Gilthunder explained to Howzer that the Chimera is the reason why he worked for the Holy Knights because that creature would harm Margaret, and is lightning-immune, if he went rogue. When Howzer apologized for not being there to help him, Gilthunder accepted it anyway. Gilthunder remained silent when King Arthur introduces himself to the group.
When Vivian teleported the group to the Lost Forest, Gilthunder held Margaret close to him as the Holy Knight mage proclaimed that they'll never find their way out of the kingdom. But suddenly, the whole group was teleported back and witnessed Vivian being teleported randomly almost immediately. It was then revealed that the one who was doing it was Merlin of the Deadly Sins who teleported the group to Liones Castle and freed Bartra and Elizabeth. During the event, Gilthunder and Margaret admit that they knew Dreyfus killed Gilthunder's father and that they were blackmailed by Vivian to keep quiet. After Dreyfus admit his crimes and sent to jail, the castle was attacked by Hendrickson who the latter awakened the Demon blood inside of the New Generation and made them into hybrid of Demons themselves. Meliodas and Gilthunder were furious at Hendrickson's cruel nature and attacked him, until they realized that Vivian took Margaret and Elizabeth hostage. Hendrickson then stabbed both Meliodas and Gilthunder to the three girls shock as Vivian thought that she was going to be with Gilthunder forever, never leaving her. However, Hendrickson explains that Gilthunder will never leave her as a corpse to her shock. Elizabeth decided to go along with Hendrickson to save Meliodas' life, to everyone's shock. Hendrickson accepted her offer and was only planning to spare Meliodas, but he will spare Gilthunder as a bonus. As Hendrickson left with Elizabeth, Margaret and Vivian were worried over Gilthunder's condition as Hendrickson's ability, Acid, was effecting him.
However, when Ban appeared and dragged Gilthunder, Ban tossed the weakening Gilthunder toward the monster, Jericho, to Margaret and Vivian's shock until Ban used Hyper Recover Speed to heal Gilthunder and Diane at the same time. Gilthunder, along with the other Holy Knights, rejoin and surround Merlin's Old Castle to prevent Hendrickson from escaping as the Holy Knights now know the true enemy. When the Holy Knights were troubled by the fact that the two Great Holy Knights were the true villains and the Deadly Sins were innocent, Gilthunder comforted them and convinced them to fight for the sins. However, when Hendrickson easily defeated the Deadly Sins with his new form, Gilthunder along with the Holy Knights still charged toward Hendrickson, but all were easily defeated. As the battle rage on, one of Elizabeth's friends, Hawk, was killed during the battle which awoke a large light beam that came from Elizabeth. When Gilthunder believed the light to be the after life, Margaret quickly explained that it wasn't as Elizabeth unleashed her true power while revealing that Elizabeth has unknowable healed many people in her lifetime. When Elizabeth's healing light healed all the Holy Knights, Deadly Sins and people in the city, it didn't heal those who have been killed and despite Gilthunder being fully healed, he still felt great fear as Hendrickson came closer to him, as Gilthunder believed there was no hope left until Meliodas kicked Hendrickson in the face, saving Gilthunder, and he regained his hope.
After Meliodas defeated Hendrickson, Bartra reappeared and regained order within the kingdom alongside Merlin. As the Holy Knights kneel for Bartra, the king thanked Gilthunder for protecting Margaret while he was unable to, which led to Gilthunder to request a private chat with the king which Bartra accepted.
After the major event, Gilthunder appeared in the Boar Hat as he is dressed casually and wanted to chat with Meliodas who was feeding the revived Hawk. The two sat down and enjoyed the drink Meliodas offered as Gilthunder drank Bernia ale, which he admitted tasted good. While the two sat, Gilthunder revealed that he was going to quit being a Holy Knight and become a wanderer as he needed to clear his mind from the sins he committed as a Holy Knight despite the fact that he was working undercover and trying to protect Margaret. Meliodas didn't argue with Gilthunder because he is no longer a child, but still wondered how Margaret will take it. The next day, Gilthunder bid farewell to Margaret, and the two shared a kiss. The day after that, Gilthunder is present in the Seven Deadly Sins´s ceremony. After the ceremony, Gilthunder, Howzer, and Griamore, thanked the Deadly Sins for sticking up for Dreyfus and Hendrickson despite what they had become, which led to Merlin telling them to find the truth. Gilthunder heads to Dreyfus' room with Howzer and Griamore, showing his companions a book relating to the Demon Clan. This immediately sparks their curiosity, and the three leave Liones to learn more about the connection between the Great Holy Knight and the Demon Clan.Danafor. This demon happened to be Fraudrin, a member of the Ten Commandments. However, Dreyfus offered his body to spare Hendrickson, which he did and continued to do so to this day. Hendrickson revealed that he was a changed man and wanted to free Dreyfus. Hearing this, the group agreed to work together and train to defeat the Ten Commandments, but they still don't fully trust Hendrickson.
Gilthunder and the others were soon taken to Istar, the sacred land of the Druids, where they were taken to train in the Cave of Training, but it was soon proven too difficult for them to handle. However, they attempted it once more when the Deadly Sins showed up to train as well, where Gilthunder is paired up with Howzer. Once in the cave, the two choose an Amber that holds a Clay Dragon, which is known to be immune to lightning and wind attacks. Gilthunder and Howzer end up arguing during the training, but soon worked together and came up with unique attacks for them to harm the dragons. In the end, however, Gilthunder and Howzer end up failing the training, but Jenna was still proud of them for coming up with new attacks on the spot.
After everyone finishes with their training, Gilthunder witnesses how Meliodas regains his strength that was contained in an amber goddess. When Meliodas asks Merlin to send him to where the Ten Commandments are, Gilthunder tries to convince him that it is crazy to face them alone. Meliodas says that he will only say hello to them.
After Meliodas returned after defeating Galand, he declares that they must end the Commandments by attacking them while they divide to cover all of Britannia. While everyone leaves Istar, Gilthunder wonders if the training really increased his strength. Hawk reads his power level increased from 1,970 to 2,330, which pleases him greatly. Gilthunder asks Hawk to read Meliodas' power level, determining it at 3,250. Gilthunder states that Meliodas is incredible for such amount. However, Merlin tells Hawk he skipped a zero at the end, leaving Gilthunder and Howzer stunned to learn that his power level is 32,500.
After arriving at Vaizel, Gilthunder and Howzer are separated from the rest when they all fall through some traps placed at the entrance of the giant maze. While they were touring the labyrinth, the two saved Diane and Elizabeth from some Prankster Imps. After catching up with the two ladies, all are attacked by a giant Earth Crawler. Gilthunder, Howzer and Diane manage to join forces to defeat him thanks to the intervention of a mysterious magician named Gilfrost who uses Freeze Coffin to help them eliminate the creature.
After meeting with Meliodas, Arthur and Ban, the group reaches the end of the labyrinth, where all the participants are received by Drole and Gloxinia. After kicking off the festival, Drole divides everyone into teams of two. Gilthunder is paired with Gilfrost and set to fight with Silver and Quazzo. Gilthunder feels some familiarity in the magician.
During the battle between Gowther & Jericho vs. Escanor & Hawk, Escanor skillfully deceives the two Ten Commandments and injures them. Meliodas quickly takes advantage of the opening and attacks his former comrades, prompting Drole to trap all the other participants and use them as hostages. Imprisoned beneath the earth, Gilthunder see himself unable to break free, to which Gilfrost suggest teleporting everyone to a safe location, successfully arriving at the Kingdom of Liones. Gilthunder sees the battle of Meliodas against Drole and Gloxinia in a crystal ball, marveling by him be able to surpass both of them. When Meliodas is overtaken by all the Ten Commandments, Gilthunder requires Gilfrost to send him with Meliodas, but Gilfrost refuses, claiming that he would only be sending him to his death. While Gilthunder insists, he discovers the ring on Gilfrost's finger, realizing his true identity.
In the end, Gilthunder can only see with pain how Meliodas is killed by Estarossa.
After witnessing the battle between Escanor and Estarossa, Howzer declares that they must evacuate the castle. Despite Gilthunder's complaints, Howzer convinces everyone that they must protect the king and the princesses first and foremost. When the knights and civilians of the city arrive and begin to attack them due to the Piety Commandment of Zeldris, Denzel offers his body to the goddess Nerobasta to be his vessel and face the demons, just to get being killed.
Gilthunder and the remaining knights attempt to evacuate the castle, but are cornered by Fraudrin and Grayroad, who captured every ordinary human in the castle in her eggs to turn into demon servants. Gilthunder tells Fraudrin that things would be different if Meliodas were there, although Fraudrin says there really would not be any difference.Margaret tells Gilthunder that she is not afraid of death while she is at her side. However, Gilfrost interposes between the two claiming that he will not let Gilthunder die, revealing his true identity as Vivian. There, she teleports along with Gilthunder out of there.
During the following days, Vivian kept Gilthunder locked up with her in a secret spot that only she knows. Gilthunder demands to Vivian return him to Liones, but she says that all of Liones must have been killed by the Ten Commandments, including Margaret. Gilthunder decides to use the curse that Melrin had put in Vivian to force her to free him, but Vivian affirms that they would remain in its small kingdom with him like the king, and she like his slave.
When Gilthunder finally finds a way out of the building where Vivian kept him, he finds out that he is in a temple high in the sky. Then Vivian appears and states that there is no way for him to leave that place built by the Goddess Clan. Gilthunder affirms that he wants to be with Margaret to which Vivian affirms that Margaret and all Liones must be dead and that they would have died as well had they not escaped. When Gilthunder tells her to shut up, Vivian declares that they must continue living for Margaret and that they can even have a daughter and name her after the princess. At that moment, a portal opens behind Vivian, from where Ludociel, after having taken Margaret's body, comes out and pierce Vivian's throat with his sword.
Gilthunder runs happily to see Margaret. However, the princess is then forced to give up complete control of her body to Ludociel. Upon seeing Hedrickson and Dreyfus there, Gilthunder alarms believing that he is Fraudrin, despite Dreyfus tries to explain that he has returned to be himself. After understanding the situation, Gilthunder asks the Archangel to return Margaret, but Ludociel says he would be disregarding the sacrifice she made to save him. There, all are attacked by Zeldris's Dies Irae, who had previously been attacked by Ludociel.
After forming the alliance between Liones and the Archangels, Gilthunder appears at the meeting where the formation for the Holy War against the Demon Clan was being decided. Gilthunder requests to go to Camelot as part of the Assault Force, claiming that he will do it to protect Margaret in the same way as Hendrickson to protect Ludociel. Ludociel agrees that they must work together as allies.
Before departing to the battle, Gilthunder share a word with Howzer and Griamore.
Gilthunder, like all Holy Knights, has magic that transcends human knowledge imbued within his body, and is among the strongest in Britannia, being able to match entire armies. He is shown to be incredibly strong and agile, easily matching Meliodas in skill and remaining unharmed after being flung from a great height and crashing into a building, destroying it in the process.He is noted to be a Great Holy Knight class according to King. After the training in the sacred land of the druids, his power level increases from 1,970 to 2,330.
- Main article: Thunderbolt
雷帝Raitei (Sandāboruto)」: Gilthunder is greatly skilled in lightning magic, being able to use it both offensively and defensively. He can use his magic to further increase his physical capabilities, granting him extraordinary strength and agility.
Gilthunder wields a long sword, through which he channels his lightning magic. The tip of the blade is curved and wider with the ends pointed.
After training in Istar, his power levels are as follows:
Gilthunder is Zaratras's son. It is unknown what kind of relationship they had but since Gilthunder wants revenge for his death, it can be assumed that they had a good father-son relationship.
Gilthunder is Dreyfus' nephew. Gilthunder displays loyalty and devotion to the Great Holy Knight though his uncle is responsible for his father's murder 10 years ago. Most likely like Hendrickson he despises his uncle due to his participation in causing his father's death but seems to regard him as the lesser evil as he gives him information on Hendrickson's actions.
Howzer and Gilthunder have greatly different personalities, but appear to fight very well as a team. However, when Gilthunder was freed by Meliodas, Gilthunder appeared a lot lighter and softer to Howzer, seeing him as his dear friend and didn't blame him for not noticing Gilthunder trouble.
Gilthunder for the most part followed Hendrickson's orders, but appeared suspicious of his actions as he gave Dreyfus information on his movements. After the creature threatening Margaret was slain by Meliodas, Gilthunder quickly stopped him from killing Meliodas, via cutting off his right arm. When Hendrickson questioned on him betraying him, Gilthunder quickly responded that he was never on his side and then proceeded to fight him, proclaiming his desire of revenge for his father.
Vivian has had an obsessive love over Gilthunder for years while Gilthunder doesn't share the same feelings. Vivian's behavior has shown to the point she holds Margaret hostage for years to get him to follow her every word, disguises herself as a man named "Gilfrost" to get closer to him and even kidnap him in the middle of a battle against the Ten Commandments and to hold him prisoner in one of the old temples made by The Goddess Clan. She is currently under the "Cursed Engagement" curse that activates under Gilthunder's command or when she inflicts her magic on him.
In the past, Gilthunder used to treat Elizabeth as a little sister. However, now, even though the kingdom's priority is to ensure her safety, he says that he doesn't care about her and that she is a "grain of sand in the path to the Holy Knight's rule". However, it was revealed that he never hated Elizabeth as it was an act, and likely still cares for her.
Gilthunder has for more than ten years been in love with Margaret and has made it his sworn duty to protect her. Gilthunder was forced to join the Holy Knights for her safety, during which he took a cold and ruthless persona. After Meliodas killed the invisible creature threatening her, he quickly dropped the act and embraced her, which she returned, after defeating Hendrickson.
Gilthunder once admired Meliodas and the rest of the Seven Deadly Sins, even wanting to be one of them. After his father was apparently killed by them, he wanted to kill them for revenge and to prove that he has surpassed his father. However, it was revealed that it was an act and Gilthunder still admired Meliodas, seeing him as his hero. Despite finding out that Meliodas is related to the Demon Clan, Gilthunder still sees Meliodas as a great knight, and there is no finer knight than Meliodas. He would seemingly give his life in order to avenge him.
- Meliodas vs. Gilthunder: Indecisive
- Diane vs. Dreyfus, Gilthunder, Howzer, & Helbram: Win
- Howzer & Guila vs. Dreyfus, Helbram, Jericho, & Gilthunder: Indecisive
- Meliodas & Arthur Pendragon vs. Hendrickson & Gilthunder: Indecisive
- Meliodas vs. Hendrickson, Gilthunder & Vivian: Win
- Gilthunder vs. Hendrickson: Win
- Holy Knights of Liones vs. Hendrickson: Lose
- Gilthunder, Howzer & Griamore vs. Red Demon: Win
- Hendrickson, Gilthunder, Howzer & Griamore vs. Gray Demon: Win
- Gilthunder & Howzer vs. Clay Dragon: Lose
- According to the databook(s):
- Daily Routine: protecting Margaret
- Special ability: Monster knowledge
- Hobbies: Thinking up monsters
- Weak Point: Loves festivals
- Dream/Hope: Become stronger than his father
- Regrets: Not being able to save Margaret earlier
- The most embarrassing thing in his life: When he misunderstood something and thought Margaret would marry a prince from another kingdom
- What he wants the most right now: The newest monster encyclopedia
- His Charm Point is his hair color
- He has a complex about his negative emotion
- The person he respect the most is Meliodas
- A person he doesn't want to make an enemy of is Meliodas.
- Gilthunder's sword changes at the start of the Kingdom Infiltration arc to a blade with curvy edges.