Monsters, Magic items and CR?

[RUMBLETiGER]

One of my buddies asked me if the Collar of Umbral Metamorphosis on a monster would increase it's CR, since it adds the dark template. I told him I didn't know.

So, I ask you, how does the use of magic items, armor, weapons, etc, affect the challenge rating of a particular monster? To the best of my knowledge I've not seen anything written about this in any official material. Draconomicon has a bunch of Dragon-specific gear, which clearly would make fighting such a creature harder, how does one gauge this? Surely a party should get more XP for fighting a Dragon equipped with the Amulet of Supremacy minor artifact (Which maximizes breath weapon damage) than fighting a standard, naked dragon.

-The option I'm considering is taking the amount of treasure such a creature is expected to drop, and if the mosnter has gear equal to up to that amount, it's included in the CR of the existing creature. I don't think I've ever played this way, usually wealth dropped by critters isn't useful for the critter itself.

What do you all think?

 

[the Jester]

I don't think I've ever played this way, usually wealth dropped by critters isn't useful for the critter itself.

Monsters intelligent enough and with the right body parts should always be using their magical gear. That's dming advice going back all the way to Basic, if not before.

 

[delericho]

I don't think this is ever explicitly dealt with in the DMG. However...

In general, whatever non-consumable items a creature has will be recovered in treasure. As such, they are their own reward. For that reason, in general you shouldn't adjust the CR for any items within the normal treasure value for the creature's CR.

If the monster has significantly better items than his treasure would normally indicate, or if those items are particular well-suited to the creature (or, equally, poorly-suited to the PCs), then you might consider giving a +1 bonus to the CR. However, I wouldn't go above a +1 bonus except in the most extreme cases.

 

[Celebrim]

CR/EL is a guideline, not a rule.

Often, some would say most of the time, you need to eyeball it and adjust accordingly.

One thing you'll notice is that the CR spectrum even for an individual CR is pretty broad. It wouldn't be unusual to add some clear advantage to a creature of a given CR, and yet that not be enough to bump up the CR of the creature. Adding 10%, 20% or 50% to the given XP under the circumstances is often perfectly valid.

A simple example would be, if an Ogre with a club is CR 3, would an Ogre with an ogre sized Masterwork Two-Handed Sword be CR 4? What about a +2 Ogre Sized Greatsword of Human Bane and masterwork chainmail? What about the huge range of options in the middle?

Another more complex example is, "What is the EL of a medium-sized skeleton?", "What is the EL of a medium-sized skeleton on Unhallowed ground?" (ei, should I count unhallowed as being a trap of its spell level, if it only buffs a single weak target?), "What is the EL of 48 skeletons?" (ei, should I count the EL as the same if the party is 1st level that I do when the party is 6th level when such an encounter is now trivial due to the parties high AC, area of effect attacks, and clerics ability to destroy skeletons in mass?), "What is the EL of 48 skeletons on unhallowed ground, created with a feat that grants them +2 Str and +2 hit points?" (ei, "Is this now enough of a buff to make them relevant?" In many cases, the best answers are not to follow the rules, or to treat the answer as not a change in EL but a change in awarded XP for that encounter level.

If you treat CR/EL as hard rules without thinking things through its going to be really easy to get in trouble.

 

[Dwimmerlied]

If the monster were advanced or had character levels, this would be easier to answer, I think; in this case, if the value of the collar were within its listed equipment allowance, then it would not, as far as I can tell increase its CR RAW. If you've chosen to add the collar to the encounter, effectively adding the template, then It seems a good idea to adjust the CR to reflect the ceature with the template; this should reflect the guidelines in the absence of rules for this kind of thing.

Also, I suppose this might also point out two distinct issues; that is, that CR serves as an indication of whether the characters will be able to handle the encounter, which can always be tested pre-game, and also how much reward in terms of experience the characters should earn for an encounter. I guess this last issue is not so much game breaking if you err one way or another, and I'd personally be inclined to do something like Cerebrim has suggested and consider awarding a certain value over otherwise listed.