The final Nintendo Direct for Super Smash Bros. Ultimate unveiled the new Spirits adventure mode, where all characters except Kirby have been turned into trophies, or Spirits, and you have to rescue them. Additionally, non-playable fighters were turned into Spirits. In multiplayer battles, Spirit characters can be assigned to a fighter, and fight alongside them. There are Metroid Spirit characters, including a Zebesian, Metroid, and Adam Malkovich. None of those characters were shown in gameplay during the Direct, but appeared in brief glimpses. The game is only a month away from release, and we’ll be sure to keep you updated on any new Metroid content that is shared!
UPDATE: Our friends at Wikitroid have confirmed three more Metroid-related Spirits: the Ridley Robot from the end of Metroid: Zero Mission, a blue Mech from Metroid Prime: Federation Force, and Samus in her military uniform from Metroid: Other M. You can see Rosalina & Luma equipped with the latter in the Direct at around 12:35. The Ridley Robot and Mech Spirits are confirmed on smashbros.com.