D&D 3E/3.5 3.5 Energy immunity vs. fire or cold immunity

[Karei]

In the DMG, the entries of Fire Immunity and Cold Immunity say the creature who has them also has vulnerability to the opposite type.

In the MM the same descriptions are given, except they are under specific elemental subtypes.

Is immunity to fire or cold energy type the same as Fire or Cold Immunity, as in the DMG entry? My DM seems to think so, while I think that Fire or Cold Immunity only applies to the elemental subtypes, or where a monster's entry specifies.

For example: A red half-dragon is immune to fire, but it does not have the [Fire] subtype like a full red dragon does. Therefore, does a red half-dragon have Fire Immunity (and thus vulnerability to cold,) or, lacking the [Fire] subtype, does it have immunity to fire but not the vulnerability?

I'm looking for evidence from an "official" source. In other words, the books, errata, FAQ, etc.

 

[Rath the Brown]

I don't know if it will help you, but the Rules Compendium updated the wording:

A creature that has immunity to energy is never harmed by that energy. A creature that is immune to fire usually has vulnerability to cold—see Vulnerability to Energy. Creatures that are immune to cold typically have vulnerability to fire.

 

[Sekhmet]

Unless stated explicitly, don't assume all creatures with immunities have corresponding vulnerabilities (the Balor comes to mind as one specific case).

-Withdrawn, see next post.

 

[frankthedm]

In the DMG, the entries of Fire Immunity and Cold Immunity say the creature who has them also has vulnerability to the opposite type.
>>>>>>>>>>>>>>>>>>>>>>>>>
I'm looking for evidence from an "official" source. In other words, the books, errata, FAQ, etc.

The official answer is right there in the book. It is often overlooked or outright ignored, but many creatures, notably a good chunk of undead, should be taking extra damage from fire attacks. The outright ignoring of this rule is another nail in the coffin of Evocation. The Entry in the Rules change Compendium is a cop out to cover for the folks who screwed this up over the years of 3E.

Cold Immunity
A creature with cold immunity never takes cold damage. It has vulnerability to fire, which means it takes half again as much (+50%) damage as normal from fire, regardless of whether a saving throw is allowed, or if the save is a success or failure.

Fire Immunity
A creature with fire immunity never takes fire damage. It has vulnerability to cold, which means it takes half again as much (+50%) damage as normal from cold, regardless of whether a saving throw is allowed, or if the save is a success or failure.

 

[Sekhmet]

I think the rule was meant to read that Cold & Fire Subtypes automatically had vulnerability, but [MENTION=1164]frankthedm[/MENTION] is correct, RAW states immunities come with vulnerabilities.
I must withdraw my previous protest.

 

[Omegaxicor]

Doesn't the Rules Compendium overrule the DMG being more recent?

either way like many things in D&D, the rules are there but open to some interpretation from DM to DM

my opinion no not all immunities carry associated resistances

 

[emoplato]

Yeah, Rules Compendium overrides it as there are actual subtypes that carry these features to qualify the difference of an immunity alone. Also if you look at Searning and Piercing cold metamagic abilities these bypass resistances and immunities but only does half damage to the similar subtypes. Plus, remember many celestials have either acid or electricity immunities, what are they vulnerable to? What about the saint template? It simply makes more sense both in balance and in figuring out what does what in addition what they qualify for to have immunities just be an immunity(especially since they are hard to come by vs. resistances).