Monster: Embergeist

Type: Undead
Challenge Rating: 5

Description:
An Embergeist is the burning remnant of a soul consumed by flames during an unnatural ritual or fiery catastrophe. Flickering embers float around its translucent, skeletal form, and its body radiates a faint, otherworldly glow. While it appears insubstantial, the Embergeist’s presence burns with intensity, capable of igniting both courage and fear in those who face it. It hungers for vengeance, particularly against the living who tread where it was once bound.

Traits and Abilities:

Incorporeal Form: The Embergeist can move through objects and creatures as if they were difficult terrain. Any creature it passes through takes 1d10 fire damage (Dexterity saving throw halves the damage).
Burning Grasp: Its melee attacks deal fire damage, igniting non-magical objects that are flammable.
Soulfire Eruption (Recharge 6): The Embergeist can explode in a fiery burst, dealing 5d10 fire damage in a 20-foot radius (Dexterity saving throw halves the damage). The explosion consumes some of its essence, causing it to take 3d10 radiant damage in the process.
Heat Mirage Aura: All creatures within 15 feet of the Embergeist perceive illusions of heat shimmer and flames, granting the Embergeist advantage on attacks against creatures within its aura.
Vengeful Spirit: The Embergeist has disadvantage on Charisma saving throws, as its rage binds it to the material plane.

Combat Encounter:
Embergeists are often found haunting ruins scorched by war or fire. They may lie dormant in smoldering ash until disturbed by trespassers. When attacking, they use their Heat Mirage Aura to disorient foes and their Soulfire Eruption as a devastating opening move. Groups of Embergeists often work in tandem to trap their enemies in a deadly inferno.

Adventure Hook:
The adventurers come across a once-prosperous village, reduced to ash and haunted by an Embergeist. The creature guards a cursed artifact responsible for the blaze and will only relent if the artifact is destroyed or the adventurers find a way to lay the souls of the villagers to rest.