Keen Eye

In Pokémon ChampionsGen III

Game

Pokémon Champions

This Pokémon's accuracy can't be lowered by others; ignores their evasiveness stat.

How it works in Champions

Prevents other Pokémon from lowering this Pokémon's accuracy stat stage. This Pokémon ignores a target's evasiveness stat stage.

“The Pokémon's keen eyes prevent its accuracy from being lowered.”
In-game text, Scarlet & Violet

How Keen Eye changed from game to game, newest first.

Gen VI
Prevents other Pokémon from lowering this Pokémon's accuracy stat stage. added: This Pokémon ignores a target's evasiveness stat stage.
Gen III · Emerald
… lowered. This ability does not prevent added: any accuracy losses other than stat modifiers, such as the accuracy cut from fog; nor does it prevent other Pokémon's evasion from making this Pokémon's moves less accurate. added: This Pokémon can still be passed negative accuracy modifiers through Heart Swap. Overworld: If the first Pokémon in the party has this ability, any random encounter with a Pokémon five or more levels lower than it has a 50% chance of being skipped.

Descriptions: Pokémon Showdown’s for each generation, and PokéAPI’s notes on the changes they don’t show. Champions: Pokémon Showdown.