Ren didn't fade away. The 'Fixed' system had a safety lock. Once the mana was expended, he was simply reset to Level 1.
(also known as Osawari H ) by developer Tawawa Delivery invites you to do exactly that. osawari h as you like in another world fixed
Fixing logic errors in the quest system that previously prevented players from reaching certain endings or completing specific character arcs. Gameplay Features and Interactive Depth Ren didn't fade away