Marisso originally belonged to Professor Sycamore along with Froakie and Fennekin. Sycamore decided to give Tierno their Poké Balls, so that X may choose one. At first, X wanted nothing to do with Marisso, as he was too depressed to choose one. However, Marisso was determined to join X's team, so he battled X along with Kanga. Though he lost, X was impressed by Marisso's performance and decided to let Marisso on the team.
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