The Devil's Bargain

Legendary cloak, requires attunement

This long velvet cloak is black as midnight and never gets dirty. As a bonus action on your turn, you can command it to billow dramatically, even if there is no wind.

Curse: Temptation to Sin

The cloak is posessed by the spirit of a devil who is bound to the cloak until he can obtain an intact mortal soul. He can manifest himself as a tiny imp that appears on the shoulders of an attuned person wearing the cloak. This spirit is not detectable by any means unless the devil has an active manifestation.

The devil will try to coax the attuned into performing evil acts in an attempt to tarnish the attuned's soul. These acts are small at first, as the devil has very little power; as the evil progresses, however, the power of the cloak grows.

Until the attuned accepts the devil's temptation, the cloak may be removed or de-attuned as a normal magic item. Once the first level of Temptation to Sin is activated, however, the curse is triggered and the cloak can no longer be removed.

The acts the devil tempts the attuned depend on the attuned's level and the power level the cloak has attained.

The save DC for any spells or abilities granted by the cloak should be 8 + Proficiency+ Attuned's Primary Attribute.

Level 1:

No minimum PC level

In exchange for an entertaining lie, the devil offeres to teach the PC one language of their choice between infernal or abyssal. To qualify, the attuned must succeed at a persuasion or deception check against a non-evil target that results in a theft or embarassing situation.

The devil may repeat this offering, resulting in the attuned learning both languages.

Level 2:

Minimum PC level: 3

In exchange for causing harm to a non-evil humanoid, the devil offers to teach the PC one cantrip of their choice between acid splash, fire bolt, and poison spray.

To qualify, the attuned must take some action that results in physical harm to the target, or significant material damage to their posesssions.

The devil may repeat this offering to teach the attuned all three cantrips.

Level 3:

Minimum PC level: 5

In exchange for killing a non-evil creature of at least CR 1, the devil offers to more fully share their growing power. Once per long rest, as a bonus the attuned may elect to have their primary weapon deal fire damage instead of its normal damage type for one turn. The uses/long rest increase by 1 for every subsequent level of Temptation to Sin the cloak gains.

The devil may repeat this offering to allow the attuned to imbue different elemental damage types to their attacks.

Level 4:

Minimum PC level: 7

In exchange for destroying a good-aligned or beneficial structure or building, the devil offers to augment the attuned's body in some way:

Eyes: Darkvision. If the attuned already has darkvision, the range is doubled. The attuned's eyes develop a red glow.

Hands: Claws (STR based, proficient. 2d4+str damage). If the attuned already has a claw attack, add 2d4 damage. The attuned's nails turn into sharp, black talons.

Legs: +10 Speed bonus. The attuned's feet turn into devil hooves.

In addition, the attuned may no longer have a "good" alignment, and the "Remove Curse" spell will no longer break the attunement to this item.

The devil may repeat this offering to grant the attuned multiple augmentations.

Level 5:

Minimum PC Level: 10

The devil tempts the PC with a taste of true power. In exchange for murdering a good, sentient creature, the devil offers the ability to transform into a fiend once per long rest. The attuned must choose between a Bearded Devil, Hell Hound, or Nightmare when the deal is struck. The ability works as Wild Shape and lasts for a number of rounds equal to the attuned's proficiency bonus.

The devil may repeat this offering to grant the attuned multiple uses per long rest.

In order to qualify, the attuned must attack and kill a non-hostile good aligned target, in such a way that the act will be discovered and recognized as a murder.

Level 6:

Minimum PC level : 12

The devil tempts the attuned with the ability to summon some of the devil's own minions. In exchange for ruining, corrupting, severely damaging, or destroying a good or beneficial powerful organization (such as a church, school, hospital, charity, etc), the devil offers the ability to summon a Chain Devil once per day (as Conjure Fey spell). You always summon the same fiend by name. Should the summon die, the devil will divulge to you another name to summon.

The devil may repeat this offering to increase the CR (either by stat or type) of the minion summoned by this ability.

In addition, the attuned may no longer be any alignment that is not evil, and their body takes on several devilish physical traits (DM choice).