Appan's Demonic Core Hammer

A mighty warhammer, it has been lightened to allow space for a dangerous, toxic magical reactor, dubbed the Demon Core. While this weapon packs less of an initial punch than its mundane counterparts, the Demon Core's innate necrotic radiance more than makes up for it. At the click of a switch, the core's lead seal can be slightly undone.

As a bonus action, the wielder can activate Appan's Demonic Core Hammer for 10 minutes. All creatures within 15 feet of the activation must roll a DC 15 Constitution Saving Throw or take 1d10 necrotic, 1d10 poison, and 1d10 radiant damage and have their maximum HP reduced by a total equal to the damage dealt until cured with a Lesser Restoration spell (or one with similar poison-curing effects). Otherwise, the creature takes only half damage. Any creature that is immune to poison, necrotic, or radiant damage is completely immune to these effects, including damage.

Upon entering or beginning a turn within 15 feet of Appan's Demonic Core Hammer, a creature must make the DC 15 Constitution Saving Throw or suffer its effects. The hammer can only be unsealed once per Long Rest and cannot be resealed until the 10 minutes have passed.

Hiding behind 3 feet of dirt, 1 foot of stone, or 1 inch of lead negates the effects of Appan's Demonic Core Hammer

Proficiency with a Warhammer allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Damage: Poison, Damage: Necrotic, Damage: Radiant, Versatile, Push