keen-eye

Effect:

This Pokémon cannot have its accuracy lowered. This ability does not prevent 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. 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.