마왕의 신부 ~용사님은 마왕의 신부~

When I woke up from my sleep in the subway,

"What?! I'm your legendary HERO?!
And... wait a minute!!!!
Are you telling me that... I have to marry a Demon Lord?!!?!"

Do I really have to marry these Demon Lords? How did I end up in this strange world?!

A story where you 'just happened' to marry a Demon Lord.