Responses
I think there's a few out there with this concept. Maybe this one?
https://www.mangago.me/read-manga/datte_maou_sama_wa_kare_ga_kirai/
It was a full colour manhwa but thank you!
Anyone know the name of a yaoi where a guy is selected to be the hero that defeats the demon king and has to train by resisting his desires? I remember there being a scene where he got some kind of temporary magic tattoo.