Death Burst. When the cinder hulk dies, it leaves behind a cloud of cinders and smoke that fills a 10-foot-radius sphere centered on its space. The sphere is heavily obscured. Any creature that moves into the area for the first time on a turn or starts its turn there must succeed on a DC 16 Constitution saving throw or take 10 (3d6) fire damage. The cloud lasts for 1 minute or until it is dispersed by strong wind.
Multiattack. The cinder hulk makes two Slam attacks.
Slam. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit:16 (2d10 + 5) bludgeoning damage plus 10 (3d6) fire damage.
Wave of Cinders (Recharge 5–6). The cinder hulk emits a wave of smoldering ash from its face, hands, or chest in a 30-foot cone. Each creature in that area must make a DC 16 Dexterity saving throw. On a failed save, a creature takes 31 (7d8) fire damage and has the blinded condition until the end of its next turn. On a successful save, a creature takes half as much damage only.
Cinder hulks are distant descendants of fire giants who isolated themselves from the world and steeped themselves in the energy of the Elemental Planes. Over the course of centuries, these giants were transformed into Elementals made of smoke and cinders. Half the size of their giant ancestors, cinder hulks maintain the basic physical shape of fire giants, but ash and embers billow around their barely cohesive physical forms.