civilized 1155/1357(85%)hp 646/646(100%)m 1402/1402(100%)mv 39880tnl (-126.59%) 6 PM demandtrib orc
You can only demand tribute from orcs, kobolds, goblins, bugbears, gnolls, and hobgoblins.

civilized 1155/1357(85%)hp 646/646(100%)m 1402/1402(100%)mv 39880tnl (-126.59%) 6 PM con orc
Your best guess is that he is a troll.
He is a member of the berserkers' guild.
You could kill Vrudish the Orc Captain with your little finger.
Vrudish the Orc Captain is about the same size you are.
He grins evilly with you.

Note that it says only from "orcs, kobolds, goblins, bugbears, gnolls, and hobgoblins", and notice that when you consider Vrudish that "Your best guess is that he is a troll.".

Demandtribute doesn't work on trolls.

If you look at Vrudish, it is apparently the intent he be considered a troll.

So I'm marking this as working as intended.