Iko Karstein, the 23rd Princess of the Karstein family. A hot-tempered vampire with a superiority complex, seeing herself as a high class vampire with astounding power, however using her powers causes her to burn a lot of calories (leaving her hungry and needing for more blood) thus she doesn't use them very often unless her temper gets to her.
Iko has set her ideals high, dominating the world and all humans, for this she needs power and now she has found a way to obtain such it: "Czernobog's" blood, a grim-reapers blood. A legend passed down in the vampire world since ancient times. One human every 300 years possesses it. If a vampire were to drink even a little of Czernoblog's blood it would get a reapers power and the ability to destroy everything. So if Iko got her hands on some of that blood she can destroy "Abraham" and make the world under the vampires control.
But this seems to have backfired as the blood enslaves her rather than give her power, as Iko is now unable to drink anybody's blood other than Akira, the blood owner of Czernobog. This causes Iko to sometimes be mistreated by Akira as she is now dependable on her for blood, like being commanded to do chores and more. After a freak-out of Iko, who refusing to accept her fate went berserk out of hunger and attacked many humans for their blood, but she was unable to digest any due to the Czernobog blood's effect and thus failing to silence her hunger until Akira showed up to calm her down, things began to settle down.