Corrupted Smith

Molten Flesh. A creature that touches the Smith or hits it with a melee attack while within 5 feet takes 3 (1d6) fire damage.

Forge-Bound Fury. When the Smith drops below half its hit points, its hammer flares white-hot. Its melee attacks deal an additional 7 (2d6) fire damage until the end of combat.

Heated Body (Recharges after a Short or Long Rest). As a bonus action, the Smith can cause its body to glow with molten heat for 1 minute. While active, it sheds bright light in a 15-foot radius, and all creatures that start their turn within 5 feet of it take 3 (1d6) fire damage.

Multiattack. The Corrupted Smith makes two Hammer attacks.

Molten Hammer. Melee Weapon Attack: +6 to hit, reach 5 ft., one target.
Hit: 11 (2d6 + 4) bludgeoning damage plus 7 (2d6) fire damage.

Throw Molten Iron (Recharge 5–6). The Smith hurls a glob of molten metal at a creature within 30 ft.
Ranged Spell Attack: +4 to hit, range 30 ft., one target.
Hit: 14 (4d6) fire damage, and the target must succeed on a DC 14 Dexterity saving throw or have its movement speed halved until the end of its next turn as molten iron clings to its armor or skin.

Forge’s Pulse (1/Day). The Smith slams its hammer into the ground, sending out a wave of heat and ringing metal. Each creature of its choice within 15 feet must make a DC 14 Constitution saving throw, taking 10 (3d6) fire damage on a failed save or half as much on success. Objects and nonmagical metal gear glow red-hot until the end of the Smith’s next turn.

Scorching Reprisal. When hit by a melee attack, the Smith can release a burst of heat. The attacker must succeed on a DC 13 Dexterity saving throw or take 5 (1d10) fire damage.