D&D 5E accounting for NPC allies when determining encounter difficulty

[pukunui]

On page 92 of the DMG, it says "When determining the difficulty of a combat encounter (see chapter 3), make sure to include all NPC party members." That section of the DMG seems to be referring to NPCs built using PC rules, which would be easy enough to account for. But what if the NPC ally hasn't got class levels? What if the NPC is a veteran or, say, a unicorn? How do I include them in my encounter difficulty calculations? Do I just use their CR as their "level"? So a unicorn would count as a 5th level party member, while a veteran would only count as a 3rd level party member? Or something else? Anyone got any ideas?

 

[AaronOfBarbaria]

The way I've been handling is to count each NPC that isn't built by the PC rules as a PC of a level equal to their CR, and it has worked well enough (because the encounter building guidelines are "soft" be design, and the game is resilient enough that being a bit off on encounter building math doesn't do any harm to game play).

 

[NotActuallyTim]

You could just count it as an advantage, and bump the encounter difficulty down by one.

 

[Mouseferatu]

I usually just say "While you guys are fighting the undead I've actually specified, your centaur allies are fighting that other group of undead over there."

IOW, give the NPCs something halfway plausible to do and then handwave it.

 

[pukunui]

[MENTION=1288]Mouseferatu[/MENTION]: What if the NPC is central to the encounter and/or it isn't plausible to add more enemies for the NPCs to deal with?

 

[Mouseferatu]

I try to avoid setting things up that way.

But honestly, if I have to, I just eyeball it. I don't worry about precise calculations. It's more trouble than it's worth, IMO.

 

[pukunui]

Fair enough. Not everyone does it that way, though. In this case, I want to know if adding a unicorn to the party will make things too easy. I don't think it will, but I'd like I have a better idea than just an eyeballed one (perhaps because I don't trust my eyeballs).