A delinquent gets sucked into another world through a mirror. He then ends up saving a guy who turns out to be an alpha and a royalty. The alpha tells him that he is his fated mate, turns out his body changed when he got sucked into this world and he became an omega. Long story short they live happily ever after. Felt like this story was milked.... Didn't like it. It could have been short but nope.
Yankee Ω wa Kemono Ou-sama no Mono!