Kaeru is an essential part of the id wells in _ID: Invaded_. She is a prop created by the Mizuhanome System to aid the "brilliant detectives" in solving crimes.

Spoiler

Kiki Asukai was the last victim of the "Challenger". She was rescued by Hunetaro Momoki before she could be killed and is currently missing.

Spoiler

It is later revealed that she became a part of the Mizuhanome System after being kidnapped by John Walker.