How does negative energy interact with shadow dragons?

Question

I'm going to be running a shadow dragon in a game soon and after reading this question,

Are negative levels necessarily energy drain?

I became confused about how negative levels and negative energy would affect a shadow dragon since it's not undead, yet it bestows negative levels with it's breath weapon and is immune to energy drain.

Are shadow dragons immune to negative energy? Is their breath weapon something other than negative energy? If so, then what causes the connection that grants them immunity from energy drain instead of an immunity from negative levels since it's been established (see linked question) that negative levels can and do exist separately from negative energy? Does their breath weapon give rise to wights since wights are formed by being killed by negative levels as via this quote from the SRD under Energy Drain And Negative Levels?:

A character with negative levels at least equal to her current level, or drained below 1st level, is instantly slain. Depending on the creature that killed her, she may rise the next night as a monster of that kind. If not, she rises as a wight.

Would they be under the shadow dragons control if so? If an undead tried to use their energy drain on a shadow dragon, how is it that the immunity functions since a living shadow dragon should technically have positive, living energy to drain? Would it's breath weapon empower/heal undead?

I realize this is a lot of questions but I'm hoping since they're interrelated I won't have to make a separate post for each one. If I do need to, I apologize and will do so.

Answer 1

To start with: shadow dragons don't have any particular connection to negative energy. Rather, they have a connection to the Plane of Shadow which grants them an ability which mimics one of the things that negative energy often does: energy drain to inflict negative levels.

So, on to the specific questions:

Are shadow dragons immune to negative energy?

Nothing in the shadow dragon's description suggests that it's immune to negative energy.

Is their breath weapon something other than negative energy?

Yes: it's "a cone of billowing, smoky shadows". If it was negative energy, it'd say so.

If so, then what causes the connection that grants them immunity from energy drain instead of an immunity from negative levels since it's been established (see linked question) that negative levels can and do exist separately from negative energy?

Shadow dragons are immune to energy drain because their entry in the Draconomicon says they are. Since it's something they have from the time they're a wyrmling, it's likely to do with their innate connection to the Plane of Shadow.

Does their breath weapon give rise to wights since wights are formed by being killed by negative levels...?

That does seem to be the case, yes. Nothing about the general Negative Energy rule is altered by the shadow dragon's Draconomicon entry.

Would they be under the shadow dragons control if so?

Nothing in the dragon's description says that those slain by their breath weapon raise under their control; compare to the vampire which explicitly states that a drained victim becomes a vampire under the original vampire's control. So, no.

If an undead tried to use their energy drain on a shadow dragon, how is it that the immunity functions since a living shadow dragon should technically have positive, living energy to drain?

A shadow dragon is simply immune to Energy Drain. Thus, an undead (or any other creature) who tried to use an Energy Drain effect on the dragon would find that the attempt failed. A vampire would find that they gained no temporary HP after attempting to drain a shadow dragon.

Would it's breath weapon empower/heal undead?

Not categorically, though I wouldn't be in the least surprised if there are specific undead out there who would be empowered by energy-drain effects.

Note that the undead type does grant immunity to energy drain, so the vast majority of undead creatures would ignore the effects of the shadow dragon's breath weapon.

Answer 2

Q1: Are shadow dragons immune to negative energy?

Energy Drain and Negative Levels

Some horrible creatures, especially undead monsters, possess a fearsome supernatural ability to drain levels from those they strike in combat. The creature making an energy drain attack draws a portion of its victim's life force from her. Most energy drain attacks require a successful melee attack roll—mere physical contact is not enough. Each successful energy drain attack bestows one or more negative levels on the opponent. A creature takes the following penalties for each negative level it has gained.

Breath Weapon (Su): A shadow dragons breath weapon is a cone of billowing, smoky shadows with an energy drain effect. Creatures within the cone gain 8 negative levels: the saving throw to remove the negative level is 39. A successful Reflex save (DC 39) reduces the number of negative levels by half (round down).

While the shadow dragon's breath weapon has not specified if it is negative-energy-based, it says it is an "energy drain" effect. The original descriptive text of the energy drain effect has not specified if it is negative-energy-based. So the breath weapon does not have to be related to negative energy (while Death Ward has no problem negating it).

Special Qualities: Energy drain immunity, Shadow blend, Mirror Image, Dimension door, Nondetection, Shadow walk, Create shadows, Frightful Presence DC39, SR 33

Also, while shadow dragons have energy drain immunity, they do not have negative energy immunity and are alive. So other negative energy effects can affect them without an issue.

Q2: Does their breath weapon give rise to wights since wights are formed by being killed by negative levels as via this quote from the SRD under Energy Drain And Negative Levels?

Yes, since there's no other description saying that's not the case.

Q3: Would they be under the shadow dragons control if so?

No, since the description does not say so. Monster would have the description saying that the newly formed undead creature follows their command if that's the case.

Q4: If an undead tried to use their energy drain on a shadow dragon...?

That energy drain attack won't work, as Energy drain immunity is part of the dragon's special quality.

Q5: Would it's breath weapon empower/heal undead?

An undead creature possesses the following traits (unless otherwise noted in a creature's entry).

—Not subject to critical hits, nonlethal damage, ability drain, or energy drain.

So nothing would happen.

Let me know if I am missing anything.