Does Auril retain effects or conditions when changing form?

Question

(spoilers ahead for Rime of the Frostmaiden, read at your own risk)

While discussing monsters with changing stat blocks, the example of Auril, from the adventure Rime of the Frostmaiden, came up.

Auril has different forms, which come into play when her previous form is reduced to 0 hp. Here are the relevant texts from the first and second forms:

Divine Rejuvenation. When Auril drops to 0 hit points, her body turns to slush and melts away. Auril instantly reappears in her second form, in an unoccupied space within 60 feet of where her first form disappeared. Her initiative count doesn't change.

Divine Rejuvenation. When Auril drops to 0 hit points, her body collapses into shards of ice, whereupon Auril instantly reappears in her third form, in an unoccupied space within 60 feet of where her second form was destroyed. Her initiative count doesn't change.

It seems unclear whether those forms are considered as different monsters altogether, or if it is the same monster changing its stat block upon reaching 0 hp. The consequence of that is that it is also unclear whether ongoing effects, magical or not, may persist through a form change. It could seem logical to make a ruling that "physical" effects, such as poisons or being stunned, do not persist, but what about magical effects or mind afflictions?

The question is then the following: is there anything I missed in the text that states if those forms are separate monsters, or one and the same? How does that influences ongoing effects and their resolution when changing forms?

I'm looking either for answers based on the text as written, or for "good subjective" answers on how a group dealt with this issue in an actual session.

Answer 1

The DM must use discretion.

The rules don't say Auril is freed from any existing conditions or effects, so we can't just say "yes all effects are ended", but there are some effects that don't make sense to have continue when she changes form. For example, suppose Auril's first form is restrained by Evard's black tentacles:

When a creature enters the affected area for the first time on a turn or starts its turn there, the creature must succeed on a Dexterity saving throw or take 3d6 bludgeoning damage and be restrained by the tentacles until the spell ends. A creature that starts its turn in the area and is already restrained by the tentacles takes 3d6 bludgeoning damage.

Technically, Auril's transition to her second form and reappearance within 60 feet does not end the effect of Evard's black tentacles, but this doesn't really make sense; she melted away and reappeared outside of the spell's area. She shouldn't be restrained anymore. However, it seems more reasonable that the effect of dominate monster might linger through transitions:

You attempt to beguile a creature that you can see within range. It must succeed on a Wisdom saving throw or be charmed by you for the duration. If you or creatures that are friendly to you are fighting it, it has advantage on the saving throw.

While the creature is charmed, you have a telepathic link with it as long as the two of you are on the same plane of existence. You can use this telepathic link to issue commands to the creature while you are conscious (no action required), which it does its best to obey.

It's seems reasonable to rule that the mental connection afforded by dominate monster may not be severed by the transition and reappearance. So the DM just needs to make a ruling. There are some effects that intuitively should not persist through her transition, but the rules don't explicitly say that the transition ends any effects (with one exception, see below).

Transition to the third form does end the Prone condition.

As a final note, if you happen to knock Auril's second form prone, it should be observed that her third form is immune to the Prone condition, so her transition to the third form would automatically end the Prone condition.

Answer 2

Each new form has new game statistics, the rest is up to your DM

All three stat blocks share the same mental stats, and of course all are Auril, she "has" those forms. The adventure text states

After finishing a long rest, Auril regains any of her forms that were destroyed, provided that at least one form survives.

so we can assume that they also share her consciousness and memories (about those pesky adventurers that just killed her previous form, for example).

Other than what we have for the druid shapechange ability, there is no additional text in the adventure that lists any special rules that would apply for transferring traits or effects between the changing stat blocks. This just would follow the general rules.

It is established that spell effects will transfer when you move to a new form. Spell effects that are invalid for the new form likely will be suppressed while in that form. Exhaustion generally will transfer (but all her forms are immune to it, just like to a number of other conditions, so that does not matter for Auril). For those that affect her, you have to evaluate that on a case by case basis -- grappled might not, invisible might.

Auril is unique, and this is exactly the kind of situation that warrants the DM applying their judgment in ruling how various things work for her.