Ultrawoman Grigio is a female Ultra Warrior, and is the younger sister of Ultraman Rosso and Ultraman Blu. She first appeared in Ultraman R/B The Movie.

Grigio means "Gray" in Italian, a name shared with a species of kaiju in the series. Despite this, their Japanese names are spelled and pronounced differently: Ultrawoman Grigio vs Grigio Bone. The former Katakana was indeed from Saki Mitsurugi's true name, which Asahi adopted as her Ultrawoman alter-ego in her memory.

During the battle against Ultraman Tregear and Snake Darkness, Asahi had transformed into Grigio Regina. However, her attacks, as well as those of Ultramen Rosso, Blu and Geed were ineffective against them. As they were about to be beaten, Saki Mitsurugi's spirit reached out to Asahi, who unlocked her true power. Grigio Regina's exoskeleton then split open, and Ultrawoman Grigio emerged from it. Restoring the energy of the three Ultra Warriors, she helped them against their opponents but they were still outclassed. To finish the battle, the Minato siblings joined hands and called upon the Makoto Crystal, fusing Rosso, Blu and Grigio into Ultraman Gruebe, joining Geed Ultimate Final in a more evenly-matched battle.