Mythra

Mythra is one of the main characters from Xenoblade Chronicles 2; she is an Aegis (or Legendary Blade) that can be wielded by the game's main protagonist, Rex. Aside from having a sword form, she also has a human form.

She was revealed to be the upcoming DLC fighter for Super Smash Bros. Ultimate's Fighter Pass 2 on February 17th, 2021. She is expected to be released in March. Her and Pyra both function as one character, with players having the option to switch back and forth between Pyra and Mythra, much like how Zelda and Sheik functioned in Super Smash Bros. Melee and Super Smash Bros. Brawl. Prior to being revealed as fighters, both Pyra and Mythra were spirits.