In the battle where Anne and Pray defeat the High Rank Beast Type 2 - Fang Blade while they were all still trainees, she's wounded and barely manages to survive after being pulled out of the Danger Zone by Anne.
Jill's mother, who works at the cafeteria in the Core Temple on Arin, thanks Anne after the battle for saving her daughter. Though she survived that battle, Jill's nervous system was damaged beyond what the medical nanomachines could repair and was told by doctors that she could no longer fight as a Knight. 
Still, she didn't give up on being a Knight, and has fought in multiple battles, continuously getting hurt. By SE 430 over 80% of her body had already been replaced by prosthetics.
She later appears on the 7th Colony of Arin, stuck there by the strong solar wind whilst en-route to Arin. During her stay, the Beasts send a Number 387 battleship to attack the colony. After retrieving her AB Sword Number 12. Tuesday, Jill gets pushed back and loses an arm while fighting the commanding unit, Type 77 High Rank. When her brother Allen tries to help he gets fatally injured. Enraged by this, Jill finally defeats the Type 77 with a single attack full of emotion. With tears in her eyes she listens to her brother's last feeble words as he slips away.
Second Battle of ArinEdit
- Main article: Second Battle of Arin
Third Battle of ArinEdit
- Main article: Third Battle of Arin
Jill participated in the Landfall Operation. She was the central defense of the 7th Colony of Arin which was designated as the battering ram to break through the Beast blockade. She willingly chose to sacrifice herself, knowing that the least her weak self can do would be to open up Anne's path.