He's called an Arrancar, and since he's one of the ten strongest, he holds the rank of Espada too. Arrancars are kind of like vengeful spirits, except they've got more clarity of mind. They just don't feel things the way people still do because they're missing their hearts. It's actually a little sad!

[At least, she thinks so.]

He's changed a lot since he got here. But not entirely. Grimmjow-san can be a little rude, so please be patient with him!

[Actually, Peter might be a good influence. Orihime can only demonstrate so much as a girl. Peter, however, is a guy, so if Grimmjow has someone he can more easily relate to...]