Jillian was a tall slim young woman with middle hair.
She wears the usual feminine Holy Knight uniform with chest-plate armor.
Like the other Dawn Roar, Jillian was willingly to kill anybody for their mission. Jillian was shown to dislike King's human form when the fairy transformed into his former form in order to prove that they're the Seven Deadly Sins.
Despite the Holy Knights' coup, Jillian retains loyalty to the king as she and her teammates obeyed Baltra's orders to restrain Slader from hurting himself and arrest former Great Holy Knight Dreyfus after the latter admitted his crime.
Not much is known about Jillian's history but at some point of time, she joined the newly-formed Dawn Roar after the Seven Deadly Sins disintegrated 10 years ago.
Jillian and the Dawn Roar, were ordered by Helbram to travel to Ordan where a local knight spotted a Armor Giant in the forest. Once Slader and the Dawn Roar travel to the location, they bring along a group of knights to which they were beaten or killed by the Armor Giant who turns out to be a Seven Deadly Sins member Gowther. Simon asks Hugo if he knows Gowther to which Hugo answers that he has seen him on wanted posters and that he is one of the Seven Deadly Sins. Slader then orders the group to make a stand off against Gowther and attack when he makes a move. Slader and the rest wait for half an hour until a young boy named Pelliot comes to them and attacks Gowther, thinking he is a dangerous criminal. Gowther is about to smash Pelliot until another boy named Armando comes in and saves his life but gets smashed instead. Slader and the rest knew the time to attack was now to which they jump on Gowther.
While King fights with Hugo, Jillian traps King in a special trap ability which makes the latter unable to move. When Armando reveals himself to be Gowther, Jillian is surprised and King turns into his fat form which broke her trap. Jillian and the Dawn Roar later leave Ordan when Gowther offers the giant's head to them.
Weinheidt and the other Dawn Roar members witness Slader's valiant attempts to save the royal family, but unable to do so due to the Perfect Cube spell placed by Vivian. Baltra orders the Dawn Roar to stop Slader from harming himself at which they immediately do but Slader refuses to leave Baltra, despite the Dawn Roar pulling him away. When the Seven Deadly Sins and Dreyfus' group suddenly appeared out of nowhere via Merlin's teleportation, Jillian and her teammates were surprised and readied their weapons just in case. Later, after Dreyfus confessed his crime and willingly surrendered, Jillian used her wire-like trap to cuff the former Great Holy Knight ready for escort to his cell for later judgement. But before that happened, the castle was suddenly destroyed by Hendrickson but Jillian was saved by King's Bear Form of Chastiefol. Jillian, however was attacked and killed by Dreyfus, actually Fraudrin who then went off to fight Hendrickson along with the other Dawn Roar except for Slader and Simon.
Jillian's corpse was placed in the morgue alongside Weinheidt's and Hugo's where Slader and Simon mourn for their deaths during the National Foundation Festival.
As a Holy Knight, Jillian is extraordinarily powerful. She also have the ability to cast a wire-like trap around her opponent as shown as when she managed to temporarily immobilize the Armor Giant's fist to allow Simon and Hugo an opening for an attack and then entangle King with it.
Manga and Anime Differences
In the Kingdom Infiltration arc, Jillian and the majority of Dawn Roar were with Slader in the king's bedchamber and stopped their captain from hurting himself in Baltra's orders and was seen using her power to restrain Dreyfus in his arrest after he admitted his crime of murdering Zaratras and framing the Seven Deadly Sins but was later killed by the former Great Holy Knight; but in the anime, Jillian was with Dawn Roar on another mission and participates in cleaning up the New Generation mutants in the city and later appears at the side of their king in the National Foundation Festival.