Kuro is the Servamp of Slot.
He is a very complicated vampire, and at the countrary of his Eve, Shirota Mahiru, he doesn't want to take any action to have no regrets later. He always says that everything is a pain, that he can't deal with things, and that he has not any will to get involved in whatever life will show him, because doing nothing problematic is the way to live a quiet life.
Speaking of this, Kuro is not just the embodiment of sloth himself, he is a singularity of a vampire. A hikikomori vampire and a dogged gamer. He is not interested in sucking his Eve's blood, at the countrary, he wants to eat ramen, potato chips and drinking cola. He spends Mahiru's money with no concern and he likes to be petted in his animal form, that is like the one of a cute black cat. That's why Mahiru called him "Kuro", even if his real form is the one of a big, black lion.