Let's consider the facts, coming from a neutral party as myself.
Cobra sometimes refers to you as Cherry, a past name you don't seem too hot on. You have also stated in the past that you--erk. Enjoy your meals with him. From what I have seen, you've only exclusively fed off him and Almaz, though Almaz is not with us anymore. There was also the first time he met you here, where he claimed to be your father, though that was kind of skeevy so I don't blame you if you don't remember that. And most importantly, you usually refer to him as Master.
. . .and I may not understand how vampires work, but if someone's sharing their life blood with you, I think it's safe to consider them as pretty damn important if only for that.