Helm of the Lichfiend (Patreon)

Wondrous item, very rare (requires attunement by a warlock or wizard)

This helm is made of carved bone and gilded horns from a powerful demon. While wearing it, you have resistance to fire and necrotic damage. In addition, once on each of your turns when you slay a Medium or smaller fiend or humanoid, you can cause that creature to erupt in a pillar of hellfire. Each other creature of your choice within 10 feet of the slain target must make a DC 16 Dexterity saving throw. A creature takes 4d6 fire damage on a failed save, or half as much damage on a successful one. When this happens, the slain creature's fleshy remains are incinerated, leaving only an animated skeleton behind with the following changes:

• The skeleton is on fire, shedding bright light in a 20-foot radius and dim light for an additional 20 feet. It has immunity to fire damage.
• The skeleton deals an extra 1d6 fire damage to any target it hits.
• A creature that touches the skeleton or hits it with a melee attack while within 5 feet of it takes 1d6 fire damage.

The skeleton remains until you finish a long rest or you use an action to dismiss it, or until it's reduced to 0 hit points. You can have up to three skeletons at a time in this way. If you already have three skeletons when you slay a fiend or humanoid, you can't use the helm to create a pillar of flame or skeleton. The skeleton obeys your verbal commands (no action required by you) and takes its turn immediately after yours. If you don't issue any commands, it defends itself from hostile creatures, but otherwise takes no actions. At the end of its duration, the skeleton's bones crumble away and collapse into a small pile of coal.

It was beautiful irony. The fool hero's words drew such crowds, the helpless looking to his shallow smile for reassurance and protection.

There was nothing he could do as glowing bolts struck throughout the crowd, and in an instant it became a pyre.

There was nothing he could do as bones rose from the ash, tearing through those who had no will to flee.

And there was nothing he could do as, each time a burning frame shattered under his maul, the pyre reignited and his enemy was rejoined.