A hundred years prior to the events of Hoopa and the Clash of Ages, Hoopa appeared in its Unbound Form in Dahara City. It ate the villagers' food, but in return, it gave them huge piles of pure gold, allowing the small village to prosper and grow into a big city. Hoopa received a home at the village, granting the villagers all their wishes. When some people wanted to see if Hoopa could beat another Pokémon in a battle, it proceeded to summon strong Pokémon, like Dragonite and Steelix, to fight them for people's amusement. It defeated all of its opponents, and the villagers cheered for it the whole time. However, Hoopa eventually got carried away, and started to summon even Legendary Pokémon, such as Zekrom, Reshiram, and Regigigas, to fight against it. As a result of these monstrous clashes, the entire Dahara City was leveled to the ground. However, Ghris soon sealed Hoopa's power into a Prison Bottle he had created to stop its rampage, and reducing Hoopa into a much smaller, Confined Forme.
Over the recent years, Hoopa was taken care of by Ghris's great-grandchildren, Baraz and Meray in the Arche Valley. As seen in Hoopa — The Mischief Pokémon, Hoopa enjoyed playing with the siblings, especially the more playful Meray, and their friends during their youth. During the events of Hoopa and the Clash of Ages, one of Hoopa's pranks resulted in it pulling Ash and Pikachu through its ring to it. It quickly became friends with the two, playfully calling them "Ashkan" and "Pikan" respectively. Ash's friends soon joined them and met Meray.
Later, the group encountered Baraz, who had retrieved the Prison Bottle from its hiding place. Upon touching it, he had however become possessed by Hoopa's Unbound Forme's power, which forced him to release it from the bottle. Upon being released, Hoopa Unbound took over Hoopa's body and went on a rampage, forcing Meray to reseal it back into the Prison Bottle. Baraz and Meray explained Hoopa's backstory to the group, also explaining why Hoopa couldn't travel through its own rings. The Prison Bottle was later stolen by Team Rocket, and Hoopa Unbound possessed Meowth to make him open the bottle once again. Baraz and Meray helped Hoopa to resist the power taking over it, and eventually succeeded in preventing that. Unfortunately, the Prison Bottle then suddenly broke into pieces, and Hoopa Unbound formed from the unsealed power. Baraz explained that the form was in fact Hoopa's "shadow", formed of Hoopa's anger of being imprisoned for a hundred years. It had destroyed the Prison Bottle to prevent itself from being sealed again. Fortunately, Baraz knew how to create a new Prison Bottle, so he and the rest of the group headed to Dahara Tower to do so, while Ash and Pikachu protected Hoopa from the shadow.
Hoopa summoned Lugia to battle the shadow, and later also Latios, Latias, and a ShinyRayquaza as reinforcements. In counter, Hoopa Unbound summoned PrimalGroudon, Primal Kyogre, Dialga, Palkia, Giratina, and Kyurem to fight against them. A climactic battle ensued, during which Baraz managed to recreate the Prison Bottle, which was then once again used to seal Hoopa Unbound. Unfortunately, Ash ended up touching the bottle, causing him to become possessed by the shadow. Thankfully, Hoopa was able to make up with the shadow, dispelling the darkness inside it and setting Ash free. Hoopa then proceeded to save the citizens of Dahara City from the space-time distortion caused by the summoning of all the Legendary Pokémon, even overcoming its disability to travel through its own rings in the process. Afterwards, Hoopa decided to help in repairing the damages done to the city before returning home with Baraz and Meray.
Personality and characteristics
In its Confined Forme, Hoopa is a very simple-minded, innocent Pokémon who loves to pull pranks on unsuspecting people. It playfully referred to Ash and Pikachu as "Ashkan" and "Pikan", and would use its ability to summon everything and anything for its own amusement. Despite its playful and mischievous nature, Hoopa has a good heart and is capable of protecting its friends when the time is needed. Hoopa also loves donuts, not only for their delicious taste, but also for their shape.
Hoopa's Unbound Forme started out as a little arrogant, but deep down decent Pokémon, offering the people of Dahara City loads of gold and wishes in return for food and a place to live in. However, when it started to battle other Pokémon for people's amusement, it soon got carried away and started to summon even Legendary Pokémon to prove its superiority, causing massive destruction in the process. A hundred years later, the Unbound Forme's anger of being imprisoned inside the Prison Bottle for all these years resulted it going in a rampage, attempting to take over its body and wipe out its personality from existence. Eventually, the darkness within it was driven away, allowing Hoopa to utilize its Unbound Forme without losing control.
In both forms, Hoopa likes to be unpredictable, often asking, "Were you surprised?" and referring to itself in third person. When using the rings to summon something it occasionally uses the catchphrase "Alléhooparing" (Japanese: おでましAppear), derived from the phrase "Alley-oop". It also refers to its summoning as "ringing".