Anime/Manga Logics And Info/Rating

owari no seraph

Anime about yu and Mika
(I think, I dont remember)
2 boys Who are Both orphan and they are forced to give vampiers their Blood
Mika and yu came up with an Escape plan to go back to the normal human world but yu has to leave his familie and Mika behind couse they were kiled by the Upper vampire
Years passes and yu has become part of a society against vampiers and they fight them
A big Battle starts but Mika Comes Back with a suprizing turn of event