Slader's long, light blue hair is unkempt and reflects his general appearance. Clothed in a ripped shirt and jeans, he is protected by only his armored gloves and boots.
During the time when he was kidnapped by savages, he wore nothing but a piece of cloth and had scruffy long hair. After he was saved by King Liones, he adorns a collared shirt and a proper set of clothes.
A natural leader; Slader was shown to have great patience, both when dealing with a dangerous enemy or instructing his less experienced comrades. When undergoing a mission, Slader is entirely focused on achieving success at any cost. His tenacity to see the mission reach completion is shared with the other members of the Dawn Roar, best shown when they stood motionless for over half an hour in wait for the Armored Giant to strike. Willing to risk his own life and the life of his comrades, he is shown to be both fearless and excited when in battle, though is more than prepared to retreat when the mission objective is reached.
Before he could even remember, Slader, who was nameless at the time, was kidnapped by barbarians and was treated like a dog as he grew up and could have been killed at any moment if he stepped out of line with the them. In order to survive, Slader would watch barbarians as they fought one another and take notice of how they engaged in combat. Eventually, he awakened his power "Overpower" as he scared off two savages. When he was nearly hunted down and about to be killed, he was saved by King Bartra Liones. The king took him in and raised him, having taught him what is to be human and named him "Slader", earning the latter's complete loyalty and devotion to the king of Liones.
At some point of time, Slader and Hugo accompanied King Bartra on his way to Camelot on a meeting with King Uther Pendragon. There he and Hugo patiently waited for their king who was having a conversation with a young boy who would later become the new king of Camelot.
Ten years later, Slader would later become the captain of the newly-formed Dawn Roar to replace the Seven Deadly Sins after they were supposedly disbanded.
PlotHoly Knights group Dawn Roar, were ordered by Helbram to travel to Ordan where a local knight spotted the Armor Giant in the forest. Once Slader and the Dawn Roar travel to the location, they bought along a group of knights to which they were beaten or killed by the Armor Giant who turn out to be a Seven Deadly Sin] member Gowther. Slader order his group to make a stand off against Gowther, until he make a move and then they should attack. Slader and the rest were waiting for half an hour until a young boy named Pelliot came to them and attacked Gowther, thinking he was a dangerous criminal.
Gowther was about to smash Pelliot until another boy named Armando came in and saved his life but got smashed instead. Slader and the rest know it was the time to attack to which they jump on Gowther. As the Dawn Roar attack Gowther, The Seven Deadly Sins came to save Gowther. Meliodas managed to stop their attack, but Slader rushed toward Meliodas and pined him down. Slader later left Meliodas to Simon and cause heavy damage to Gowther's armor. But then the crush boy Armando got up and put a stop to one of their attacks and revealed himself to be the true Gowther.
As soon as the air cleared up, Slader got excited to fight off the Deadly Sins, but realize that they have to get the Armor Giant kid, to which Gowther point out that it is impossible due to the Armor power which the Dawn Roar sense. Slader realizes he couldn't beat it despite losing some men of his group, but Gowther later cut off the Armor head and give it to Slader, in order to avoid an all out battle which would affect the Ordan villages. Slader accepts the offer but told him that if he got the mission to take his head and left with his group.
After taking a break, the Dawn Roar began discussing themselves of the events they witnessed and wondered why Helbram sent them to such a mission though he has the New Generation to handle it. Slader stood in front of the Armor Giant's head and Weinheidt wished to see behind the mask, but Slader reminded his teammate that their mission is to take the head of their target not to look at it. Little did Slader and his team knew of Jericho's presence who was eavesdropping in their conversation.
While on his day off, Slader found Gowther facing against three Holy Knights which Slader defeated them with ease and fought against Gowther, which he was looking forward to for a long time. Slader start attacking Gowther while the latter dodge his attacks as Slader tell him if he believe in fate which Gowther said that things happen so is not fate. Slader mention that he wanted to fight Gowther for so long, and was surprised to meet him so soon, but Gowther said there is no reason to fight until Slader said that the Deadly Sins betray the king and grow angry because of their reason. Gowther stop his blade and told Slader that he have to end this quickly until Slader use Overpower on Gowther and break his neck. Slader went into thought at how the king saved him until Gowther stood up unjury despite his broken neck and saw his memories. Slader was shock to see Gowther in good shape. Gowther told Slader that now they do not have a reason to fight since they both serve the Royal Family, but Slader refuse, saying that the Dawn Roar replace the Deadly Sins which Gowther mistook as Slader as his junior and shake his hand which Slader shake it off.
Gowther told Slader that the king really told him that the Deadly Sins are the traitor which silent Slader, but said that the king was sick and did not told him, but the Great Holy Knights, but Gowther ask if the king really told him which shock Slader and walk away, realizing he made a mistake. Shortly later he is shown at the door of the Kings private chamber requesting an immediate audience after having managed to force his way to it by slaying several Holy Knights. As Slader goes up to the main door, Slader slices the door to open it, but the door remain unscathed and he ends up being sliced instead. Vivian reveals that the Royal Bedroom is protected by Perfect Cube which wouldn't allow anyone who uses force and that said force bound at him. King Liones told Slader that he should not worry about him, but Slader continued to slice the door as he was touched by the king's kindness toward Slader.
After numerous attempts to break in, Slader finally collapsed on the floor, with blood coming out and his mask half broken. However, Slader stood up and once again, attempted to break in. Dawn Roar witness Slader's valiant attempt and Bartra ordered the Dawn Roar to stop Slader at which they did, but Slader refuses to leave Bartra behind. Bartra told Slader that he will be fine without him and that Slader should not break the door with brute force as it will bounce back to him. As the Deadly Sins and Holy Knights were teleported to the Chamber by Merlin help, Dawn Roar were surprised to see them there. Slader was upset to see Gowther due to his current situation and that Gowther could laugh at him if he wants which the latter did emotionlessly to his and Dawn Roar's annoyance. Once Bartra was freed from his prison, he ordered that Slader must receive medical attention at once to Simon and Hugo. Later after Dreyfus willingly surrendered for his crimes, Slader looks in shock and anxiety when he saw his king suddenly coughed up blood, but Merlin intervened to treat him. When Meliodas was being offered position of Camelot's Great Holy Knight by Arthur, the Dragon's Sin of Wrath accepts the offer and states that Dawn Roar is more qualified to replace the Seven Deadly Sins as the kingdom's strongest group of knight while looking at Slader whom he nods. Then suddenly the castle was destroyed by Hendrickson and Slader was saved by King's Bear Form of Chastiefol.
During the chaotic battles between Holy Knights and the New Generation-turned-Demons by Hendrickson, a still-wounded Slader tells Simon to focus on the battle. Later after the situation around the capital has been contained, Slader and Simon joins the Holy Knights surrounding Merlin's old castle while the Sins dealt with Hendrickson inside. Slader later appeared in front of Merlin's old castle as he was ready to face Hendrickson while the Deadly Sins face him. When Hendrickson appeared with a new form and killing some Holy Knights, Slader step in and used Overpower to trap Hendrickson, while ordering Simon to attack him and sent him to several other Holy Knights as they combine their power, but proved no use against Hendrickson.
Post-Kingdom Infiltration arc
At the National Foundation Day Festival, Slader and Simon mourned the deaths of their comrades at the morgue where their corpses are placed.
Later, Slader, Simon and the rest of the Holy Knights were struck by Gowther's Blackout technique and rendered unconscious. Somehow, Slader regained consciousness and wakes up the king while realizing what caused everyone to suddenly black out linking to Gowther. Arriving on the scene, Slader approaches Merlin and bows before her in respect after the latter tells him that she has a favor to ask him despite Meliodas' warning that Slader only obeys the king. Upon witnessing this, Meliodas accuses the Dawn Roar captain of being blackmailed but the latter denied it, stating that he respected the Boar's Sin of Gluttony for freeing the king from the Perfect Cube-covered royal chambers which he had a hard time trying to break through it and wanted to call Merlin "my lady". After agreeing to Merlin's request, Slader was shocked of Gowther's reveal of being a doll after the Boar's Sin of Gluttony used Absolute Cancel on the Goat's Sin of Lust that reverted him back to his true form.
At the Boar Hat, Slader holds on to Gowther's doll form and meets Hawk for the first time. The Dawn Roar Holy Knight agreed to accompany the Sins to Camelot since they're down to three members with King, Ban and Escanor missing and Gowther out of commission for now on per orders from King Bartra to aid them. Later after Elizabeth ran off after Meliodas denied her to accompany along on their journey to Camelot, the Dawn Roar captain finds the Dragon's Sin of Wrath an insensitive man and gives an advise to the third princess that "women swoon at men's words and men swoon at women's actions" just from his opinion, earning a giggle from Elizabeth. When Merlin decided that they're going to Camelot right away, the Boar Hat was teleported right away flying near the mysterious giant figure where Slader and the three Deadly Sins prepare for battle against it.
Even among the Holy Knights, Slader is noted to be very powerful by Meliodas and a highly capable combatant. Slader has a high degree of strength as he was able to lift and swing his large weapon with ease.
- Main article: Overpower
- Overpower「威圧 （オーバーパワー） Iatsu (Ōbāpawā)」: Slader is capable of overwhelming his enemies by exerting a malicious aura that temporarily immobilizes them. He can use the time they are incapacitated to both subdue them or quickly end their life.
He wields a jagged, saw-like blade in battle.
While there wasn't much interaction between the two, Slader and Hugo did work together for a number of years, working together since at least the time King Bartra met a young Arthur. After hearing Hugo and his fellow Dawn Roar teammates' deaths, Slader mourned for him.
Out of all the Dawn Roar, Slader appears to be the closer to Simon and fight along well with one and another, despite the two share different ideas about being a Dawn Roar Holy Knight.
Seven Deadly Sins
Slader holds Gowther in high respect since the first time they met and see him as a form of a rival. Slader wanted to fight Gowther out of the rest of the Deadly Sins before learning that the sins did not actually betray Liones. Slader has shown to have some romantic interest in Gowther . Slader was put in charge of watching Gowther in his doll form, and was also seen affectionately dressing Gowther after the sin turned back into his human form.
While the two haven't had any noticablee interactions, it is shown that Slader has gained much respect and admiration for Merlin after she freed Bartra and Elizabeth with ease using her Absolute Cancel ability, while he was unable to despite great effort and injury.
After Bartra gives Slader food, water, and a place to live, Slader swears total loyalty to Bartra and becomes one of the King's greatest knights. Slader would even sacrifice his own life in order to save Bartra and even get touch by the King's kindness.
Armor Giant arc
- Dawn Roar vs. Armor Giant: Indecisive
Kingdom Infiltration arc
- Gowther vs. Slader: Indecisive
- According to the offical databook(s):
- Special ability: Make-up!
- Hobbies: Dates
- Weak Point: His butt
- Dream/Hope: Serving Bartra for the rest of his life
- Regrets: Making his comrades go with Dreyfus
- The most embarrassing thing in his life: Nothing
- What he wants the most right now: I never wanted this and I will never want this
- He has a womanly manner of speech.
- His name was previously unofficially translated as Threader.
- His mask serves as a "switch" between his two ways of speech.