Manga by author Ato

Radel, a normal human, had a special transformation after an accident 50 years ago. He saves Sien from a life-threatening situation caused by Veron, and the two decide to live together to search for Shakia, who holds the key to the accident 50 years ago. Their relationship is initially based on mutual needs, but subtle feelings quickly develop between them."I just... feel good when I touch you."