Alucard x Anderson - Kiss Me, Animal 

Their love is a visceral one. They sing this for each other.
So happy to have finally found a song that so perfectly speaks to me in regards to my favorite manga/anime (Hellsing). Bonus, for my OTP from it.
Quite fittingly, this has turned out to be a 666th sub marker, as well as an accidental birthday post. Cheers. XD