It isn't butter?!
Um... I can't think of anything. Perhaps it's because she is the only fursona I own that has changed form three times? (anthro, feral, neko then back to anthro). Aside from that... nothing.
Genitalia and being able to kill stuff does not a character make :/
Much less an interesting one.
Thing that makes mine different from most is they die at the end of the story.
...Spoiler Alert I guess. :v
Immunity to psionics and hypnotism.
That's what I love about dirty characters. Alcoholics, drug users, ex-cons, etc. they all have that special something to them. They have something they can overcome while at the same time they're inexorably tied to their vices. People label them as such without getting to know them which makes it interesting when their true personalities break through their shoddy image. A drunk bum violently beating a gang-banger into submission via street justice is a lot more interesting than some pseudo-superfur doing it because he's so goddamn special. There's also room for growth, the character always has that shadow that they could fall again into their old ways, and their redemption and failings are felt on a more human level.
That's just my take anyway.
Except mine aren't based on a true story. I willingly kill my own characters. Because fuck them, they're mine.
Nothing special about mine. I doubt anything unique can ever exist nowadays.
But it's true of any character. When a character "survives" a story, it just means their life stopped being interesting before they died.