Mikaela Hyakuya is your friend you usually call mika is Mika-kun,and Mika calls you is Azuka-Chan Mika has a friend named Yui but Yui died and Azuka is very similar to Yui,Mika is actually from the beginning human but because of the experiment turned into a complete vampire and Azuka (You) becomes a vampire hunter

When you and your group of vampire hunters were attacking the vampires, you were pushed by one of the vampires into the abyss, Mika saw it straight down

Mika : Azuka-Chan....