Crissann, the Scorned

Ephemeral. Crissann can't wear or carry anything.

Incorporeal Movement. Crissann can move through other creatures and objects as if they were difficult terrain. He takes 5 (1d10) force damage if it ends its turn inside an object.

Flickering Flame (Recharge 5-6). As a bonus action, Crissann can teleport up to 30 feet to an unoccupied space he can see.

Blazing Illumination. Crissann sheds bright light in a 5- to 30-foot radius and dim light for an additional number of feet equal to the chosen radius. Crissann can alter the radius as a bonus action.

Superheated Air. Any creature that starts their turn within the radius of bright light created by Crissann's Blazing Illumination trait must make a DC16 Constitution saving throw. On a failed save, the creature takes 10 (3d6) fire damage and is blinded until the start of their next turn. On a successful save, the creature takes half as much damage and is not blinded.

The superheated air ignites all flammable objects in the area that aren't being worn or carried.

Fuel for the Fire (2/Day). As a bonus action, Crissann can target one creature it can see within 5 feet of it that has 0 hit points and is still alive. The target must succeed on a DC 16 Constitution saving throw against this magic or die. If the target dies, you may choose either Crissann's Seething Supernova or Rise From the Ashes ability. That ability recharges instantly, without having to roll.

Legendary Resistance (2/Day). If Crissann fails a saving throw, he can choose to succeed instead.

Multiattack. Crissan makes 2 cauterize attacks.

Cauterize. Melee Spell Attack: +7 to hit, reach 5 ft., one creature. Hit: 13 (3d8) fire damage.

Invisibility. Crissann and his light magically become invisible until he attacks or uses its Fuel for the Fire, or until his concentration ends (as if concentrating on a spell).

Seething Supernova (Recharge 5-6). Crissann explodes with a violent fury. Each creature in a 20-foot-radius sphere centered on Crissann must make a DC16 Dexterity saving throw. A target takes 31 (9d6) fire damage on a failed save, or half as much damage on a successful one.

Rise From the Ashes (Recharge 5-6). Range 10 ft., Crissann directs his rage towards nearby spirits, rallying them to his cause. Crissann summons a Will-o'-Wisp in a space adjacent to any nearby corpse that did not die as a result of Fuel for the Fire. The Will-o'-Wisp acts as an ally of Crissann and shares his initiative count, taking its turn immediately after Crissann.

Collapsing Star. If an attack would reduce Crissann's hit points to 0, he may instead use his Seething Supernova as a reaction and die.

Crissann can take 2 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. Crissann regains spent legendary actions at the start of his turn.

Detect. Crissann makes a Wisdom Perception check.

Backfire. Crissannn makes a cauterize attack on any creature within range that attacked Crissann this turn.

Firebreak (Costs 2 Actions). Crissann turns invisible and moves up to 20 feet in any direction.