A curse that is inflicted on a party member by Yul'gard when near death. The curse cannot be cured unless by means of a Wish spell, replacing the afflicted's heart, or by drinking the blood of Tiamat.
An afflicted person has their heart gradually corrupted. If they undergo stress, the curse will grow, infecting the afflicted more and more until it ceases control.
* At 10% curse, the target's chest, directly over their heart, begins to mutate into an almost pitch black tone with glowing red veins.
* At 20% curse, the mutation grows across their collarbone and over their left shoulder. Spellcasters afflicted with this curse gain the Wild Magic trait from the Sorcerer class, but at half the normal percentage.
* At 30% curse, the mutation expands halfway down their left arm and down their torso. The mutation begins to grow small horn-like spikes along the afflicted person's spine. The user begins to slightly lose control of their sanity, and will occasionally lash out at others. During social interactions the player joins, the DM rolls a d100. If the result is 1-15, the user will lash out in rage.
* At 40% curse, the mutation completely engulfs the user's left arm and begins to creep down the user's legs.
* At 50% curse, the mutation engulfs most of the user's legs and the horn-like growths get larger. The effects of Wild Magic now operate normally. The user gains a +1 to their Strength and Constitution.
* At 60% curse, the mutation now completely covers the user's legs and extends halfway down their right arm. The user begins to lose control of their sanity more frequently. During social interactions the player joins, the DM rolls a d100. If the result is 1-30, the user will lash out in rage.
* At 70% curse, the mutation now covers the entirety of their body below the neck. The user gains another +1 to their Strength and Constitution but get -2 to their Dexterity.
* At 80% curse, the mutation creeps up the user's neck. The user becomes vulnerable to Radiant damage and resistant to Necrotic damage. The user becomes immune to Poison damage.
* At 90% curse, the mutation engulfs the left half of the afflicted person's face, the horn-like growths grow even larger, and their left eye transforms into that of Tiamat. The user can close their right eye in order to activate Tiamat's Sense, granting the user Darkvision up to 60 ft and Truesight up to 30 ft. If the afflicted already has Darkvision, it is increased to 120 ft. If the afflicted already has Truesight, it is increased to 60 ft. The user can rarely keep their composure due to the curse afflicting their mind. During social interactions the player joins, the DM rolls a d100. If the result is 1-50, the user will lash out in rage.
* At 100% curse, the mutation completely takes over the afflicted person's body, turning into a Vessel of Tiamat. The curse is now completely in control and the afflicted's old self is erased from the vessel's mind.
A Vessel of Tiamat is fueled by rage and the desire to destroy. The are Chaotic Evil fiends that tend to move on all fours but can stand straight up to fight.