If a have the event Arceus and you start new game will it come back?

In the Pokémon video game series, if you start a new game, any Pokémon that you have obtained in previous games will not transfer over to the new game. This includes event Pokémon, such as Arceus. Therefore, if you have Arceus in your current game and you start a new game, you will not have Arceus in the new game.