The Fiend appears as a blackened obsidian card engraved with the imagery of the 15th tarot card: a monstrous fiend wielding chains. The chains seem to shift when viewed from different angles, and the card radiates a faint pulse of heat. Whispers of temptation echo faintly when the item is held, that grow louder when its power is invoked.

Cursed Nature

This item attunes to you automatically if it is on your person during a long rest. Attuning to The Fiend automatically curses you. The artifact cannot be unattuned unless through a Wish spell or similar divine intervention. While attuned, you must succeed on a DC 20 Charisma saving throw whenever you attempt to act against the artifact’s will (e.g., aiding an enemy, showing mercy, or relinquishing power). On a failure, you are compelled to act in the artifact’s interest instead.

Properties:

Aura of Binding Creatures within 30 feet of you have disadvantage on saving throws against charm, fear, or similar effects that you create.

Infernal Pact When you make a pact (such as through a Warlock's Pact Boon or a similar agreement), the terms shift slightly in your favor. Once per long rest, you can reroll one failed ability check or saving throw related to deception, persuasion, or intimidation and Mark Corruption

Chains of Servitude (requires Corruption Level 1) As an action, you can summon fiendish chains to ensnare a creature you can see within 60 feet. The creature must succeed on a DC 18 Strength saving throw or become restrained for up to 1 minute. While restrained, the target takes 4d6 Necrotic damage at the start of each of its turns. You can release the creature as a bonus action. The chains vanish when the effect ends. You can use this feature once per long rest without marking corruption.

The Fiend's Temptation (requires Corruption Level 1) You can cast the Dominate Person spell at 5th level without expending a spell slot. The save DC is 20. You can use this ability once per long rest. Mark Corruption.

Whisper of Temptation (requires Corruption Level 2) Your Charisma score increases by 2 to a maximum of 24. Whenever you make a successful Deception or Persuasion check to convince a creature to act against its better judgment, you gain temporary hit points equal to your Charisma modifier (minimum of 1). However, you suffer disadvantage on Insight checks as the whispers of The Devil cloud your judgment and empathy.

Corruptive Ascension (requires Corruption Level 3) Once per long rest, you can undergo a fiendish transformation for 1 minute, gaining the following benefits:

• You gain resistance to fire, psychic, and necrotic damage.
• You can cast the Dominate Person spell at 5th level without expending a spell slot. The save DC is 20.
• Your melee and spell attacks deal an additional 2d8 Necrotic damage.

However, each time you deal damage to a creature during this transformation, you must make a DC 15 Charisma saving throw. On a failure, you Mark Corruption. If you fail by 5 or more Mark Corruption again.

Corruption Mechanic

The Fiend has a corruptive influence. Whenever you fail a saving throw against its abilities or use certain features (as noted above), you Mark Corruption. For every five times you’ve marked corruption descend 1 level.

Levels of Corruption:

1) Your alignment shifts one step closer to Evil. Your skin begins to darken with fiendish markings, and spectral chains appear attached to you in the astral and ethereal planes.

2) You lose the ability to regain hit points through hit dice, and you develop an irrational desire for power, and/or domination.

3) You become vulnerable to radiant damage, and The Fiend's whispers are constantly audible, even to others within 10 feet of you.

4) Your soul becomes bound to the card. If you die, your body transforms into a fiend under the DM’s control, and your soul is imprisoned in the artifact.

Corruption can only be reduced through Wish, or an act of extreme self-sacrifice as determined by the DM.

Notes: Any, Cursed