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 fight on Atop the Netherbrain if the player sides with the Emperor. It will appear if a sorcerer is present in the party.