Does Victory Star activate only when Victini is on the field?

Question

For example, I have a Porygon-Z, Magikarp, and Victini in a double battle. If Porygon-Z and Magikarp are on the field, and Porygon-Z uses Zap Cannon, will it always hit due to Victini's Victory Star(even though Victini isn't on the field)? Or will Zap Cannon always hit when Victini is on the field?

PokeDex entry of Victory Star:
>Boosts the accuracy of its allies and itself.

Answer 1

No, Victini needs to be on the field

Victory Star only works if Victini is on the field. You would need to switch out Magikarp for Victini for Porygon-Z's Zap Cannon to have 55%.

Source+Various other questions on the db