What exactly is that mark on zero's neck and how'd he get it?

WARNING SPOILER ALERT!!!!!!!



When Zero was seen scratching himself in the flashback, that was because he wanted to rid himself completely of all traces of Shizuka Hio and the fact that he was becoming a vampire. The mark on his neck is a sello meaning that he is a tamed vampire and it gives Yuuki the power to subdue him should his instincts get out of hand.

If u r a Vampire u have that mark. It looks like a tatoo.

The mark on Zero's neck is a tattoo. That tattoo is a symbol of a vampire. When he was a kid, Shizuka bit him and that's how he got the tattoo. Even though he has it, the Night Class doesn't have it because they were born o were a vampire when they were a kid. I think personally that tattoo on Zero's neck is only for when people get bitten por a pureblood.

its a tattoo