Is the Demon King a Healer?

"If you are a healer, just heal at the back."

This is the mindset of everyone in this world. Healers have been most unappreciated among combatants. But the strongest man, the 'demon king,' who is the target of everyone, was a healer?

Note: This is a new version of the story, retelling the events from the beginning with several changes and new elements added. The author released these chapters months after the original work was canceled to compete in a contest.