Page in progress—mind the dust!
Because NPCs generally follow the same rules as heroes, it might be tempted to create an NPC as if you're creating a hero.
However, there are some important differences between heroes and Guide-controlled characters.
Keep it Simple
The most important difference is that heroes should be the focus of the game. Heroes can be more complex, because only one player controls one hero. You'll likely be controlling many characters. To help keep the spotlight on the heroes:
Avoid giving your characters more than a handful of abilities.
Simplify abilities, like magic spells, that entail complicated resource management.
Minimize the dice rolls you'll need to make for the character or monster—for example, by framing an area attack as something heroes need to roll to avoid.
Only Heroes Have Callings
Heroes are designed to be asymmetrical with friends and foes. They're meant to overcome odds and win battles that would defeat other characters. The six callings' starting abilities are the main source of this asymmetry.
These abilities—Mighty Blow, Leaf on the Wind, Stratagem, and the three magical base abilities—are not just extremely powerful, they're also not fun for other players to be on the receiving end. Don't give your characters these abilities.
That said, you can mine the callings for other abilities to give your characters. Just stay away from the starting abilities.
Smaller and Larger Creatures
Unlike heroes, monsters come in many sizes. Compared to human-sized beings, tiny creatures can't inflict or take much damage, but they're also harder to hit. Larger monsters have more Life, more Stamina, pack a stronger punch, and are harder to stagger.
Tiny. Monsters of size 0 have this trait. Melee and ranged attacks against the creature suffer a -2 penalty. Take hold attacks, and close attacks while a hero grapples the creature, don't suffer this penalty.
Sturdy. Monsters of size 4 and larger have this trait. The creature takes 1 less guard damage from attacks and braces.