Pyra

Pyra is one of the main characters from Xenoblade Chronicles 2. She is a Blade, a personification of a weapon (in her case, the legendary Aegis sword) that can be wielded by the game's main protagonist, Rex. She was created by Mythra out of shame as an alternate personality and an idealized version of herself. The kind, gentle Pyra uses a variety of flame-based powers in combat, whereas her arrogant, headstrong "sister" Mythra uses light-based powers. Both Pyra and Mythra were released as a singular 2-in-1 downloadable fighter for Super Smash Bros. Ultimate, marking their sole appearance alongside Mario franchise characters.

Super Smash Bros. Ultimate
On February 17, 2021, during a Nintendo Direct, both Pyra and Mythra were announced as the fighters for Challenger Pack 9 for the Fighters Pass Vol. 2 in Super Smash Bros. Ultimate. They released on March 4th, 2021. Their reveal trailer features Rex (the protagonist from Xenoblade Chronicles 2) searching for Pyra in a style reminiscent of the original game (with the usual Smash intro transition missing so as to mislead the viewer), only to find her excitedly announce that she received a Super Smash Bros. invitation letter. Rex then laments that he thought he was going to be a fighter. After a moveset showcase that introduces Mythra and the Cloud Sea of Alrest, Mythra meets Shulk on Gaur Plain (a reference to Shulk's DLC appearance in Xenoblade Chronicles 2), then transforms into Pyra as the two exchange words and rush at each other. A follow-up presentation showcasing Pyra and Mythra's moves in-depth occurred on March 4th, 2021, followed by their official release on the same day.

Pyra and Mythra function as one character, with players having the option to switch back and forth between them, similarly to how Zelda and Sheik functioned in Super Smash Bros. Melee and Super Smash Bros. Brawl. Pyra's moves include Flare Smash, a burning slash attack that deals good damage and knockback; Flame Nova, a spinning attack that emits fire; Prominence Revolt, where Pyra leaps into the air and crashes back down to create a burst of fire; and Blazing End, a projectile attack that has Pyra throw her sword like a boomerang. Pyra's Final Smash is Burning Sword, in which Rex appears and the two create a pillar of fire that burns and launches opponents.

Pyra has near average weight, being the same weight as Mario, Dr. Mario, and Corrin, while being lighter than Mii Swordfighter and Cloud and heavier than Luigi, Shulk, and Byleth. She is also a rather slow fighter on the ground, having a slower walk speed than Peach, Daisy, and Bowser Jr., and runs slower than Villager.

However, while Pyra's overall mobility is quite low, the majority of her attacks can deal high amounts of damage and knockback on opponents, making her a rather strong fighter on offense. In fact, most of Pyra's standard attacks are fully capable of making KOs, but they are slower to execute when compared to Mythra's attacks. Thus, Pyra is overall comparable to Byleth in her characteristics.

Prior to being revealed as fighters, both Pyra and Mythra were Legend-class support spirits. Pyra's spirit battle involves fighting Lucina in a red costume, representing Pyra, and Shulk, representing Rex, on the Battlefield form of Halberd. When equipped, Pyra's spirit increases the damage dealt to Assist Trophies.

Advice to any fellow editors: Pyra isn't a Mario character.
Pyra and Mythra's Classic Mode route pits them against pairs of fighters who are similar to each other, and both Master Hand and Crazy Hand appear in the final round regardless of the current intensity.

Palutena's Guidance
Pyra and Mythra share this stock conversation with all other DLC characters except Piranha Plant. It was originally used for Mewtwo, Lucas, Roy, Ryu, Cloud, Corrin, and Bayonetta in Super Smash Bros. for Wii U, who are downloadable fighters in that game.
 * Pit: Who is THAT?
 * Palutena: I have no data on this fighter. I can't believe it!
 * Viridi: It must be an intruder from another dimension!
 * Pit: Whoever it is, the goal remains the same: to fight and win!

Quotes

 * "You'll get burned."
 * "Yeah, on it!"
 * "Burning... Sword!"
 * "Witness our power!"
 * "I'm sorry!"
 * "So long!"
 * "Smash Flare!"
 * "Prominence Revolt!"
 * "Switching!"
 * "To you!"
 * "Mythra!"
 * "Right here!"
 * "Got it!"
 * "Flame Nova!"
 * "Blazing End!"
 * "We did our best!"
 * [with Mythra] This... is the power of the [without Mythra] Aegis!"

Trivia

 * Like female Corrin and Bayonetta in the series, Pyra's design added some skin tights covering her legs in her in-game model and artwork. Unlike her counterpart Mythra, who received the same treatment in her in-game spirit, Pyra's in-game spirit has never been modified to add skin tights covering her legs.