D&D 5E Proficiency bonus for NPCs and monsters

[aco175]

I was looking at some stat blocks and was going to raise one of the to-hit modifiers since I saw the proficiency bonus was +2 for a veteran with 9hd. I saw a chart saying that the bonus is tied to challenge rating (CR) and the veteran is a CR3 creature even though it has 9HD.

Then I looked up sidekicks and see that they gain proficiency like PCs and get +3 bonus at level 5. Are they just special types of NPCs or am I missing something.

 

[LordEntrails]

NPC are not Sidekicks and Sidekicks are not PCs.

They all have different uses and rules for creation and use (unlike previous editions).

 

[aco175]

So, it appears that a sidekick is a monster or NPC that the PC met along the way and joined the party. At that point it becomes a sidekick and gains levels in the sidekick class.

This just seems to codify a set of rules instead of the DM making something up for Vera the guard, or Biscuit the mastiff.

 

[billd91]

I was looking at some stat blocks and was going to raise one of the to-hit modifiers since I saw the proficiency bonus was +2 for a veteran with 9hd. I saw a chart saying that the bonus is tied to challenge rating (CR) and the veteran is a CR3 creature even though it has 9HD.

Yeah, the HD rating is mostly reverse engineered from the hit point value you select to get the right challenge level. It actually means very little in play compared to the values derived from the CR.

 

[LordEntrails]

So, it appears that a sidekick is a monster or NPC that the PC met along the way and joined the party. At that point it becomes a sidekick and gains levels in the sidekick class.

This just seems to codify a set of rules instead of the DM making something up for Vera the guard, or Biscuit the mastiff.

No.

NPC are anything that doesn't travel with the party of Player Characters (plus can be used for some things that do travel with the party). Their HD and CR are not directly related (unlike previous editions) and they dont have class levels. They are not (normally) created using PC creation rules. They are created by the DM to have the abilities and stats needed by the DM. The CR is then calculated based upon estimates and it honestly doesn't (shouldn't) matter if you are off by an increment.

Sidekicks are lesser PCs used to round out a party that needs assistance (skill set, more damage output, etc). I.e. when you have only 1 or 2 players and they want a more rounded party but don't want a fully complex PC.

 

[LordEntrails]

Or to put this another way and go back to your OP, proficiency bonus is an intermediate tool used to create an NPC stat block. AND, it does not have to match the CR of the NPC. CR values are calculated (typically) using an average offensive and defensive CR. So the PB might by +5, but the damage, AC, HPs might mean the CR is only 1. Or the PB might be +2, HD 20 and the CR 10.

They are whatever the DM needs them to be.