Board Thread:Questions and Answers/@comment-187.237.231.124-20200817085917/@comment-36009152-20200817123633

Whist Yu was shown to  physically age it is his cursed gear and experimental link with a seraph that allows him to recover from what would be serious injuries using their magical effects. As for immortality the lifespan status is an uncertainty what with there being a past Yu as well so that's a wait and see area.