Ork. With a "
k".

Orks with a "
c" are green, stupid, and chase hobbits or D&D adventurers around.
Orks with a "
K" carry cyberdecks or drive giant Stompas. And carry big fraggin' guns.
And Bull's always been an ork

But with a name like Bull, I can see how you'd expect horns.
(I don't remember there being a Troll named Bull in any of the novels, but it's been a
LONG time since I've read some of them, so it's possible. It's certainly not the most unique handle.)
Bull