Advancing Monsters and CR

[Fester]

I am trying to get my head around monster advancement and CR. According to the MM, associated levels add +1 per level added to the CR, nonassociated levels add +1 per 2 levels added.

So, I want to put together a 3rd level rogue kua-toa. I would say that rogue is a nonassociated level, as it doesn't really add to the attack or defence capabilities of the kua-toa. That would mean the CR would be 3rd (rounded down) - 2 HD + 1 nonassociated level.

But that just seems odd, since a 1 HD creature with 3 levels of rogue would also be 3rd, but without the kua-toan extra abiltities.

So can anyone point me in the right direction of how to calculate the CR for critters with class levels? It would be most appreciated.

On a related note: according to the dmg, ECL is Level Adjustment + HD + levels. So a 1st level Ogre fighter would have an ECL of +7 (EL 2 + 4 HD + 1 class lvl). Right?

Thanks in advance.

 

[Altamont Ravenard]

The Kuo-Toa isn't in the SRD, so I'll try to build a different example.

Let's take an Ogre (4HD, CR3). If I were to add 6 Barbarian levels to this Ogre, they would be considered associated levels, and thus the Barbarian Ogre would be now considered a CR9 challenge (3 + 6)

If I were to add 6 Wizard levels to this Ogre, they would be considered nonassociated levels, and thus the Wizard Ogre would now be considered a CR7 challenge (the first 4 nonassociated levels ( =HD ) count as +½CR each, and the last 2 nonassociated levels count as +1CR each, so 3 + 4*½ + 2*1 = 7)

As for the second question, yes that 1st-level Ogre Fighter has an ECL of 7, and thus would be a good 7th-level party member, but is only a CR5 creature (and thus not a good challenge for a party whose average level is 7)

Hope this helps.

AR

 

[GiantInThePlayground]

First, I would round up.

Second, consider that maybe rogue should be associated levels. The kuo-toa gets bonuses to Spot and Search and Escape Artist, and has a few perception-based immunities and immunity to poison (allowing them to poison their weapons with impunity). Sounds roguish to me.

 

[Fester]

Thanks for helping out, guys.

Yes, I agree (in hindsight) that rogue might be considered an associated level, which would also make the CR seem fairer.

And is there a hard and fast rule about rounding up (or down) when calculating CR? I mean, you may well be right about rounding up, but I'm just curious.

Thabks again.