Mace of the Black Crown

The Mace of the Black Crown is a mace and one of the Arms of the Betrayers created by Asmodeus from the soul of an erinyes named Xartaza. As a sentient weapon, it has a Lawful Evil alignment and can communicate with its wielder telepathically. Similar to a Vestige of Divergence, the Mace of the Black Crown progresses through various stages as it is wielded and gains new properties, including giving its wielder resistance to fire and poison damage, and the ability to summon various devils.

Description
The Mace of the Black Crown is a mace, with a haft made of black iron and a head made from a ruby, and is fiendish in appearance. The mace was made from the soul of the erinyes Xartaza, who alters the wielder's dreams, pushing towards actions that would recruit souls for Asmodeus. The Mace of the Black Crown can hear up to a range of 120 feet and has darkvision for the same range.

Properties
Like all Arms of the Betrayers, it progresses through stages—dormant, awakened, and exalted—and becomes progressively more powerful as it is wielded. Each stage has all the properties of the previous stages.

Dormant state

 * One random minor beneficial property and one random minor detrimental property.
 * The wielder knows Infernal.
 * As a bonus action, the wielder can speak a command word to set the head of the mace ablaze. The flames remain until dismissed with the command word again, or if the wielder stops holding the mace. While ablaze, the mace sheds bright light for 40 feet and dim light for an additional 40 feet. If the wielder makes an attack with the mace while it is ablaze, it deals an additional 1d6 fire damage.
 * Summon Devil: As an action while holding the mace, the wielder can summon an Imp. The imp is friendly to the wielder and their companions, and for 10 minutes will follow any order the wielder gives, before returning to the Nine Hells. This feature can only be used once until the next dawn.

Awakened state

 * One additional random minor beneficial property and one additional random minor detrimental property.
 * The bonus to attack and damage rolls increases to +2.
 * The additional fire damage dealt by the mace while ablaze increases to 2d6
 * The Summon Devil feature can now be used to summon a bearded devil.
 * The wielder gains resistance to poison damage while wielding the mace.

Exalted state

 * One random major beneficial property.
 * The bonus to attack and damage rolls increases to +3.
 * The additional fire damage dealt by the mace while ablaze increases to 3d6
 * The Summon Devil feature can now be used to summon a barbed devil.
 * The wielder gains resistance to fire damage while wielding the mace.