by sniderman » Tue Feb 05, 2013 2:30 pm
Yup, Page 58 in the rules discusses Monsters and Willpower:
Monsters and Willpower
At times, particularly when mental combat arises, it is necessary to know a monster’s WIL. As a general rule, animals of generally low or animal intelligence will have WIL scores that range from 3-8 (1d6+2). Monsters of approximately human intelligence will have a WIL from 3-18 (3d6). Extremely intelligent monsters may have a WIL from 11-21 (2d6+9). These are merely guidelines, and there may be exceptions. Exceptions will be noted in monster descriptions, and the Mutant Lord may rule that some monsters or individuals deviate from these guidelines.
There's also a sample combat against vomit flies on page 55 where the ML has to determine the WIL of the critters.
I usually play it by ear depending on the creature's perceived intelligence. Insects and such will start at 1-6 (depending on my mood); animals at 6-8; intelligent humans and mutants 8-10; superintelligent creatures; 10-12. Then I'll toss a random 1d6 on top of that. If the creature has mental mutations, I'll add another 1d4 for each mental mutation. (The rationale is that it's been using its ability, thus its WIL is higher than non-mutated creatures.)