Guardian Cosmos is the mysterious guardian spirit bound to the Cosmos Crystal, dwelling within the Galaxy Cauldron. She's best known for appearing only once—in the manga's final chapter—making her one of the series' most enigmatic figures overall.
Her exact role remains deliberately vague. She seems to be the Sailor Power Guardian of both the Cosmos Crystal and Sailor Cosmos, which would tie her directly to Usagi, though she never explicitly confirms this. The manga suggests some kind of connection linking her, Queen Serenity, and Princess Serenity's birth from long ago, but the details are intentionally left for readers to piece together themselves. Fans often debate what actually transpired between them and what her guardianship really means.
Content compiled by AnimeList.moe from publicly available sources.
