Height 162 cm (5'4”) Ayase is an amazing and determined young girl who is paralyzed from the ​waist down and uses a wheelchair. She is also Undertaker's sole Endlave combat pilot. She can't stand feeling dependent on others, so she firmly rejects any and all help from others. There are two things Ayase dislikes more than anything - being offered help by others because of her disability and if someone is watching her while she is trying to crawl back into her wheelchair on her own. She believes the process itself doesn't make her look very elegant. Even though Ayase is disabled, she is valued and respected by all Undertaker members for her Endlave piloting skills. This paralyzed girl makes her Endlave which weights many tons of armor grade steel-alloy move on the battlefield with uncanny precision. Ayase being the only pilot of Endlave mobile combat platform is instrumental to all Undertaker operations. Her primary job is to draw the attention of the enemy Endlaves away from the Undertaker's main objectives and provide support and cover for other Units. Most of the time during combat Ayase finds herself outnumbered at least three to one, but still, are able to hold her own against enemy Endlaves. Originally, she piloted an older Endlave Jumeau model before it was destroyed by Daryl, but later gains Daryl's Endlave Steiner model. Ayase has feelings for Gai and is very loyal to him. She was eager to accept all responsibility for losing her original Endlave in combat, after successfully holding off multiple, newer and more advanced enemy Endlave models with her older model for 18 minutes. After listening to her report, Gai simply tells her that the fault is his own and that he is not fit to be the Undertaker's Commander for giving her such cruel order, to which she blushed furiously.

Spoiler

Ayase's Void is a compensation for the disabled girl's one and only shortcoming. It's a direct reflection of Ayase's hearts' deepest wish and decides - to be able to proudly stand on her own two legs. Something that most people take for granted. This powerful Void manifested itself as a reinforced lower-body exoskeleton providing its user with amazing agility, mobility, and jumping power. Strangely enough, it also possesses a roller-skates type capability allowing for a swift movement over flat surfaces. It is possible that because Ayase is so used to Endlaves which utilize skating instead of walking to quickly move in and out of combat - it caused the same ability manifest in her Void as well.

At first Ayase is apprehensive toward Shu, because of his lack of firm character and indecisiveness, but later on she warms up to him as she starts to see him change as a person and yet remain the same as a human being.

Spoiler

As Shu ready to leave for the decisive battle and wishes to return everyone's voids in case he doesn't come back, Ayase is the first one who tells him that she wishes him to keep her void for if Shu loses - all their lives are forfeit.