Libero

Introduced in Generation VIII, Libero changes the Pokemon's type to match the type of the move it is about to use, activating just before the move executes. This guarantees same-type attack bonus (STAB) on every offensive move, providing a 1.5x power multiplier regardless of the move's type.

Since Generation IX, Libero activates only once per switch-in -- after the first type change, the Pokemon retains that new type for the remainder of its time on the field. This was a significant competitive nerf, as the original version allowed constant type-shifting every single turn, making the user nearly impossible to predict defensively.

Found exclusively on Cinderace's evolutionary line (3 Pokemon), Libero functions identically to Protean and served as its signature counterpart for Sword and Shield's fire starter.