Physiological Mimicry: Your connection to the Corrupted Elder Dragon, Tiamat, has granted you unprecedented power. Your physical form now mirrors the dragon's influence, manifesting scales, glowing orange pupils, or eerie marks of decay. Additionally, you gain the following benefits:
- You gain immunity to the damage types associated with Tiamat's five heads: acid, cold, fire, lightning, and poison.
- Your Strength score increases to 24
- Your Constitution score increases to 24
Dragon Soul Bond: Once per long rest, you can take an action to invoke the corrupted echo's power, transforming into the form of Tiamat for 1 minute. While in this form, you gain the all of the stats, abilities, actions, and legendary actions of Tiamat.
Manifest Corrupted Energy: As a bonus action, you may take 2d10 necrotic damage and channel Tiamat's corruptive energy into your attacks. Add the amount rolled to the damage of your next successful attack. The dark energy courses through your weapon or natural attacks, leaving a lingering effect that causes the target to make a Constitution saving throw or be poisoned until the end of your next turn.
Dreadful Resilience: As a reaction to taking damage, you may tap into Tiamat's dread-filled essence, gaining resistance to the triggering damage type until the end of your next turn. Additionally, the eerie aura of Tiamat's malevolence surrounds you, imposing disadvantage on attack rolls against you until the end of your next turn. This reaction can be used a number of times equal to your Constitution modifier (minimum of 1), and you regain expended uses after completing a long rest. The number of uses increases to twice your Constitution modifier at 10th level.
Spawn Corruption: You may, as an act of desperation, unleash a surge of Tiamat's corruption upon the battlefield. You take 10d10 necrotic damage plus your level to open a portal to the Plane of Corruption. This portal summons 1d6+2 Corrupted Young Dragons, each aligned with one of Tiamat's heads, into the battlefield. They are friendly to you and follow your commands. If you are incapacitated or killed, these dragons retaliate against the enemy that dealt the final blow before returning to the Plane of Corruption.
- Additionally, your connection with Tiamat grants you advantage on saving throws against spells and effects that attempt to charm or frighten you.