Inb4 a nerd says "um akshually, that's a thousand-year-old vampire who got put in a child's body after the main character didn't want to kill them like she wanted, so she instead sulked in a corner for the entirety of the first season of the show"
It's me. I'm that nerd. And if anything happens to her, I'll kill everybody here and them myself
One thing I like about Shinobu is that she is not treated as "totally not a child". When in this child form, she is a child. No romance, no silly things.