If a Pokémon with Illuminate is in the first place in the party (even if fainted), the wild Pokémon encounter rate increases by 100%. It shares this trait with Arena Trap and No Guard.
Starting in Version 2.0.1 of Pokémon Scarlet and Violet, Illuminate prevents other Pokémon from lowering the accuracy stat stage of the Pokémon with this Ability, and also ignores the target's evasion stages.
Effects that decrease accuracy without using stat stages, such as Wonder Skin and Sand Veil, are unaffected by Illuminate.
Prior to version 2.0.1 of Pokémon Scarlet and Violet, Illuminate had no effect in battle, even after its text update in version 1.3.2. However, this inconsistency could not be seen in-game as no Pokémon with Illuminate had been available in Scarlet and Violet at the time.
Outside of battle
Illuminate appears to have no effect on the encounter rate of wild Pokémon.
Prior to Pokémon Super Mystery Dungeon, a Pokémon with Illuminate "blinks" after a turn in which it was damaged. The "blink" summons a hostile Pokémon somewhere on the floor.
In Pokémon Super Mystery Dungeon, the Pokémon obtains the Decoy status after using an illuminating move. The Decoy status makes enemies preferentially attack the Pokémon instead of other allies.
Affected moves
The table below lists the moves affected by Illuminate, as well as the Pokémon that can have Illuminate and learn those moves.
When the Pokémon is attacked, an enemy Pokémon appears somewhere on the current floor.* When this Pokémon is attacked, an enemy appears somewhere on the floor.*
Watchog holds out its arms and the yellow parts of its eyes and all the yellow stripes on its body flash yellow extremely brightly. The light then dies down a little, causing any invisible things to appear.