Ash's Naganadel (Legend Heroes)

Ash's Naganadel was the fourth Pokémon that Ash caught in the Alola region, and his fiftieth overall.

As a Wild Pokemon
When Poipole was in its home world, it lived in a nest with multiple other Poipole and an elder Naganadel. A Necrozma, in its Ultra form, also lived in the same world, whose light would make the world a lush and green planet. Although it would often protect the Poipole and Naganadel, one day a meteorite came crashing down and in order to protect the world from its impact, Necrozma collided with it. But in destroying the meteorite, it turned into a different form with a black appearance and fell into a crevasse. After falling, the change in Necrozma's form caused it to be encased in a spiky and crystallized cocoon and turned the lush and bright world into a desolate and dark place. The Poipole and Naganadel would huddle together and take in the remnants of light left. Poipole later left the world, attempting to find a better place to live.

Legend Heroes: Sun & Moon
TBA

Personality
Poipole is quite playful with other Pokémon. In one instance of this in A Mission of Ultra Urgency!, whilst Ash and his classmates were waiting to see if Buzzwole had been captured, Poipole attempted to play with Pikachu before flying off. It has also been shown to have a fascination with light, as shown how it tends to stop to admire Pikachu's Electric-type moves, much like how Ash's Goodra admired Pikachu's strength. In addition, Poipole is known to laugh even when attacked. Poipole took an instant liking to Ash after he helped saved it from Team Rocket. This was also seen when Ash showed it how Poké Balls work. Equally, it also became quick friends with its teammates. Despite being a playful trickster, Poipole never seems to intend any serious harm, as it clearly felt sorry when Pikachu scolded it for poisoning Rowlet, and offered to help carry Rowlet.

Poipole has a habit of spinning on its head when feeling happy. It also likes to express its affection for Pikachu by nuzzling him. Despite Poipole's playfulness, it has been shown to be there for its friends, like in Some Kind of Laziness!, when it rescued and brought back Rowlet after it was almost blown away by the harsh winds blowing through the Haina Desert. Poipole has also been shown to love making paintings with its ooze, especially of those whom it wishes to be good friends with, like Pikachu and Minior. As revealed in The Shape of Love to Come!, Poipole uses its drawings to express its feelings to others. It draws lighting bolt-shaped marks on or next to things that it likes or loves, and has been seen drawing teardrop shapes when feeling sad.

Being an Ultra Beast, Poipole is quite unfamiliar with the world of Ash and his classmates, and is driven by a great sense of curiosity, as seen in Real Life...Inquire Within!, when it began to play with an Alolan Exeggutor's tail head, unintentionally causing the Exeggutor to send Ash rolling out of the Pokémon Center he was in. This same curiosity almost got it in trouble with a Tauros on Kiawe's family's farm. Poipole appears to lack the ability to smell, as it was unaffected by the stench produced by Garbodor in Real Life...Inquire Within! and reacted with indifference to the aroma produced by the flowers grown by Tapu Bulu in Some Kind of Laziness!.

Trivia

 * Poipole's capture marks the first time Ash caught a genderless Pokémon.
 * Poipole is the first Ultra Beast owned by a main character.
 * As a member of Ultra Guardian, despite being genderless, Poipole wears a pendant that is commonly synchronized to be used by the confirmed male Pokémon members of Ultra Guardians.
 * Poipole also the only first known expanded Pokémon of Ultra Guardian, who is not one of its original founding Pokémon.