Victory Star increases the accuracy of moves used by the Pokémon with this Ability and its allies in battle by 10% of their original accuracy. Victory Star can stack and does so multiplicatively (which means if there are two ally Pokémon with this Ability, the accuracy increase is 21%).
Victini appears as a Poké Ball Pokémon, after playing 100-Man Smash at least once. It uses Victory Star, which causes fighters (and teammates, if any) who send it out to gain immunity to knockback and have their attack power boosted.
Raises the accuracy of moves used by the Pokémon and allies standing next to it.* The accuracy of moves goes up! It also affects allies who are next to the Pokémon.*