Was looking around for a bit, and found this post related to Owari no Seraph (Keep in mind this post is bias):
lol, you mean if there is BL? because yaoi is a genre that depicts males in erotic/porn situations and BL (boys love or shonen-ai) is "shojo" romance between two males. So to respond to your question , nope, this is obviously not yaoi or BL, its a shonen. No kisses or porn or love confessions between males.
Now if you ask "is this fujobait?"
YES. there are very close males crying at each other, bridal style "ill carry you in my arms", one pedophile vampire who loves gropping another male's ass. That's called fujobait and it sells. You shouldnt be focusing in that but in the plot...which it really becomes interesting in later chapters:D
ps-Im completely attracted to the fujobait here, since Im a fujoshi so to me the more hints, the better;P
Just like Naruto and Sasuke, people ship Yu and Mika- even more if you ask me, b/c this manga has a lot of bishounen guys. I don't ship them, and I don't see why I should. I ship couples where I see true romantic interaction, may it be hetero, gay, or lesbian. Yu's and Mika's relationship is clearly familial, not romantic -.- (Why do you think an anime like Free! is so successful? It's clearly catered to the fans who are love shounen-ai).