White Dragon Wyrmling

A white wyrmling on the party's side is the egg the ranger pulled from a poacher's sack. Run it as a foundling with one tutor (likely a PC) and the moral question of whether evil is innate or trained. Intelligence 5 means the wyrmling cannot strategize and cannot understand a long explanation. It speaks Draconic and nothing else, eats raw meat, sulks for hours when corrected, and imprints hard on whoever is feeding it.

In a fight on the party's side, the wyrmling is a mid-range artillery piece on a leash. Cold Breath at DC 12 in a 15-foot cone is the headline action, and it will cheerfully aim it down a corridor full of bandits if the party member it has imprinted on points first. Two Rends at +4 follow once the breath is spent. The wyrmling does not coordinate beyond pointing-and-biting, so if the rogue is in the same cone as the bandits, the rogue is in the cone. Warn the player. Let them pull the wyrmling's snout up before it fires.

Outside combat the wyrmling is a campaign clock. Every level the PCs gain, the wyrmling grows. The party is raising a future adult white dragon, which is a CR 13 problem in a few years' time, and the way they raise it determines whether that future dragon protects them or eats them. A wyrmling that has been treated kindly and trained against cruelty might grow up Neutral. A wyrmling that has been used as a weapon will grow up exactly the dragon you would expect. The choice is the long game.

Have the wyrmling refuse to eat for a day after the party kills something it thought of as a sibling. Don't explain. Let the table figure out what they did.

A white dragon wyrmling is the first dragon a low-level party fights, and it should feel like one. Cold immunity, four movement modes (30 ft. walk, 15 ft. burrow, 60 ft. fly, 30 ft. swim), and Ice Walk for free movement on the slick floor it has chosen to defend. White dragons are the dimmest of the chromatics with Intelligence 5, so the wyrmling fights on pure instinct: territory, hunger, and the fury of a child who thinks every adventurer wants its small pile of frozen junk.

The opener is Cold Breath if it's available. DC 12 Constitution save, 5d8 cold (22 average) in a 15-foot cone. The cone is short, so position the wyrmling to catch two PCs at most, ideally the cluster around the door. Once the breath is spent, switch to Multiattack: two Rends at +4 with 5 ft. reach, 6 slashing plus 2 cold per hit. About 16 damage per round, enough to drop a 1st-level wizard and pressure a 3rd-level fighter.

Mobility wins this fight for the wyrmling. Don't engage from the floor like a melee brute. Use the 60 ft. fly to break line of sight around an ice column, drop into a Cold Breath, and ascend again before the rogue can close. Burrow 15 ft. through compact snow lets the wyrmling vanish into a drift and reappear behind the cleric next round. Ice Walk means the icy cavern floor that costs the party Difficult Terrain costs the wyrmling nothing. Fight on the terrain and the encounter punches well above CR 2.

White wyrmlings do not understand retreat as a strategy, but they understand fear. Once Bloodied with Cold Breath spent, the wyrmling shrieks for its mother (whether or not she is anywhere nearby) and tries to burrow into the snow to hide. The party can finish it then, or they can let it flee and make a permanent enemy of whatever older white dragon hears the shriek echo through the glacier tunnels three weeks later. Either is a good ending.