Gleipnir

グレイプニル

High-schooler Shuichi Kagaya hides a bizarre power: he can turn into a giant, grinning dog-mascot monster with a zipper running down its back. When he rescues a classmate named Clair Aoki from a fire, she discovers his secret and forces a deal, climbing inside the suit to pilot his monster body from within. Searching for her missing sister, Clair pulls Shuichi into a brutal hunt for magical coins among other transformed humans.