I'd suggest using a combination of the Hireling rules, the Monster rules, and a special Move or two for when a PC interacts with the NPC in a certain way. So, here's an example from the charming little village of Gallowdell:
The Old ManSolitary, IntelligentFlesh-withering curse (d10, ignores armour)
Near12 HP
Instinct: To protect the people of Gallowdell
- Command the risen dead
- Raise corpses as undead servants
Loyalty starts at 0.
Skills: Arcane assistance, 4. Secret lore, 3. Local renown, 3.
Arcane assistance: When the Old Man assists in the casting of a Wizard spell of third level or lower, the spells effect has greter range, duration, or potency. Unlike normal Adepts, the Old Man can also assist Cleric spells of any level, providing they can be described as Necromancy.
Secret lore: When you
Spout Lore after or during a discussion or argument with the Old Man, you take +1 to the roll. Every third time you use this, the GM will also reveal an unwelcome truth.
Local renown: If you are accompanied by the Old Man, all prices within Gallowdell are reduced by 3 coin.
When the Old Man pulls you back from the Black Gates of Death, roll +Loyalty:
On a 10+, that was a close call. You feel your heart start beating again, and the grey fog recedes from your vision.
On a 7-9, you lurch back to life, but something isn't quite right... You've taken on a characteristic of the undead. Choose from the list below.
- Your heart remains still. Your skin is deathly pale and icy cold. Your eyes seem somehow empty and lifeless.
- You feel an unnatural hunger, perhaps for blood, flesh, or souls.
- A terrible fear seizes you, perhaps of sunlight, holy symbols, or fire.
On a 6-, he wasn't quick enough. Your body might stand up, but your soul is in Death's domain.