Lobo_Solitario17's manga / #hero(2)

Isekai - summoned to another world but deemed to not be the hero our OP MC goes on an adventure - marries a demon, makes human friends, kicks ass, makes demons friends and tons of adventure and fun

The Hero seeking to defeat the demon king ends up babysitting the baby demon king instead. Cute oneshot _ would be interesting to see a manga series on this