Ice Mephit

An ice mephit on the party's side is almost always a brief alliance: a bound familiar of a wizard NPC, a coward bribed with food (mephits are weirdly food-motivated in most lore traditions), or a deal struck with an ice elemental cult that wants the same dragon dead the party does. The mephit will not love the party. It will mock them in Auran and Aquan, and the cleric's player will hear every insult.

In combat, point it at clusters and let Frost Breath do its work, then use Fog Cloud to give the rogue a free Hide turn. The 30 ft. fly is a useful tool for delivering a small object to a high ledge or scouting an icy chimney shaft. Darkvision 60 ft. and Stealth +3 mean it makes a tolerable scout in dark passages, though Perception +2 and Passive Perception 12 mean it will miss most subtle traps. Treat its scouting reports as roughly true rather than reliable.

The Death Burst is a feature in the party's hands too. A mephit that's about to drop is a 5-foot Cold bomb the wizard can position with Mage Hand or Dancing Lights tricks, especially against fire-vulnerable foes. The party's healer will not heal it; mephits are 21 HP and disposable, and the mephit knows.

When the favor is up, the mephit leaves on a stolen trinket and a parting insult. Let it. A mephit who sticks around longer than agreed is a comedy beat that wears out fast.

An ice mephit is the snickering imp of cold places, and it works best as the warning shot before a real winter encounter. Use it as the first sign that a glacial cave, a frost giant's antechamber, or a wizard's frozen lab is occupied. One mephit alone is barely a fight; a flock of four to six is a problem the party will remember.

Open with Frost Breath if the party is bunched. DC 10 Constitution save, 15-foot cone, 7 cold on a fail. The DC is forgiving, but it recharges on 6, so a lucky round can stack two cones across the same melee scrum. Pair the breath with Fog Cloud (1/day) on round one to deny the ranged characters their lines of sight, then have the mephit retreat into its own fog and pop out to Claw at +3 for 3 slashing and 2 cold. AC 11 and 21 HP mean a mephit dies fast, which is fine; that's where Death Burst earns its place. DC 10 Con save, 5-foot Emanation, 5 cold on a fail. Group three mephits and the dying one's burst hits any PC mid-melee. Vulnerable to Fire (a torch swing for double damage) is the loophole every party should find within two rounds, so let the smart player who tries it feel rewarded.

Mephits do not retreat in any meaningful sense. They are spite incarnate. They will, however, fly away (30 ft.) to fetch a bigger sibling or to alert whatever runs the lair. Treat that as a campaign beat, not a combat one. If a mephit escapes, the next chamber knows the party is here.

Have one mephit cackle in Primordial as it dies. The translation in the cleric's ear is something obscene about the bard's mother. Pettiness is the brand.