Young Blue Dragon
Large Dragon, lawful evil
5,000 XP
Actions
Multiattack
The dragon makes three attacks: one with its bite and two with its claws.
Bite
Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 16 (2d10 + 5) piercing damage plus 5 (1d10) lightning damage.
Claw
Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) slashing damage.
Lightning Breath (Recharge 5-6)
The dragon exhales lightning in an 60-foot line that is 5 feet wide. Each creature in that line must make a DC 16 Dexterity saving throw, taking 55 (10d10) lightning damage on a failed save, or half as much damage on a successful one.
Quick Reference
Running This Encounter
The Young Blue Dragon is a deadly aerial combatant that should dominate the battlefield with lightning attacks and mobility. Open combat in its lair grants it maximum advantage—use legendary actions to maintain pressure between turns. Consider adding 2-3 subordinate creatures (cultists, guards, or lesser monsters) to complicate action economy and force difficult tactical decisions. The dragon should use its lair actions to create dynamic hazards like electrical surges or collapsing terrain.
Combat Tactics
The dragon prioritizes Lightning Breath on clustered enemies, dealing massive damage to force separation and positioning. It uses its superior flying speed to maintain distance from melee combatants while attacking from above, only engaging in close combat when necessary or when enemies are grounded.
Environment & Setting
Mountain peaks, storm-torn ruins, or underground caverns with high ceilings and conducting stone pillars work best. Incorporate vertical terrain that rewards the dragon's flight capability while offering limited cover for grounded adventurers.