One of the rules is make everyone human which I always took to include monsters. So monsters can communicate and have goals you can comprehend (even though they might be horrible). You can manipulate or seduce monsters although it might be a great deal more dangerous than with most people.
Tbh I have not used many monsters outside of maelstrom experiences because making a fucked up person with peculiar needs and powers is more interesting. A few true monsters I've used:
The wolf with human eyes: a big scary wolf that literally has human eyes. It's very intelligent and gathers a pack of regular wolves (3-harm hand, no armor, 2 hp like humans) around itself for which it acts like a strong leader. From time to time the pack grows to a maximum size of 40 individuals. If the
wolf with human eyes is killed it is reborn from the flesh of another wolf within a month but it will have to start from scratch gathering its pack. To stop it from coming back you need to erase it from the maelstrom, in that game it would have meant capturing it and keeping it alive since the maelstrom was the underworld created by a deadly virus. Its threat type was Alpha wolf (duh).
The thing in the mist: the players never saw it. They were in a (apocalypse: the ground has been swallowed by sinister mist) bunker and something was banging on the door. It would have been an animated corpse stretched out thin by the gravity event that collapsed the ground so it would have long limbs and a freaking neck. I'm not sure how I would have handled it mechanically, probably it would have been hard to kill with each attack maybe severing a limb but not really stopping it.
Murder of poison crows: controlled by an evil shaman. They had poisonous beaks and liked hanging out in trees outside marked peoples' homes. If you went out at night they would attack and swarm you and inflict a poison that dealt 4-harm(ap). Being nice to the shaman helped deal with this problem but so would probably a surprise explosion.
Skeleton on motorcycle: encountered in the underworld. Blinds you with the headlight and runs you over with its motorcycle.
Remember that the PCs start out powerful and quickly grow very powerful in terms of everything. Don't count on numbers to provide any sort of satisfying challenge but make monsters serve to highlight a scarcity or be connected to another threat. Or monsters can simply be a punishment for fucking up when dealing with another threat. I had some PCs exploring an underwater ruin in scuba gear and one PC had a strong fear of octopi (water apocalypse, octopuses would crawl into people's homes and steal their stuff including pets and babies) so when they opened a cupboard one obviously attacked her face and started strangling the air tube on top of being scary as hell. A failed act under fire to remove it with a sword lead to cutting off the air tube in the process of removing it which made the logistics of the trip much harder.
That was the first session at a con but a second session would probably have included two threats linked with the octopi thieves (the maelstrom was a literal maelstroms occuring in the ocean, the brainer would go freediving when opening her brain, the hocus would simply meditate floating in a flooded house).
- The depths: Breeding pit (impulse: to generate badness)
- Octopi burglars: Sacrifice (impulse: to leave people bereft) (seeing as they are not very dangerous or even very common but the people would react strongly to them, the faction that was the hocus water cult worshipped them as messengers of their watery god)