When a spell or effect would deal half damage on a successful Dexterity saving throw, it deals no damage if you succeed and only half damage if you fail.
Whenever an enemy within 60 feet targets you with a spell of a level that is lower than or equal to your proficiency bonus, you can use your reaction to nullify the spell.
Metamage Persecutor is a hostile Countermeasure Aberration character in Baldur's Gate 3 who may appear during the final battle Atop the Netherbrain if the player sides with the Emperor. It will appear if a sorcerer is present in the party.
While the player character can only use Psionic Dominance once per long rest, the Metamage Persecutor is able to use it multiple times so long as it has a reaction to spend.