Guardian Cosmos

ガーディアン・コスモス

Guardian Cosmos is the enigmatic guardian spirit of the Cosmos Crystal, residing within the Galaxy Cauldron. She makes an appearance only once, in the final chapter of the manga.
Guardian Cosmos stands as one of the most mysterious figures in the entire Sailor Moon manga. She appears to be the Sailor Power Guardian of the Cosmos Crystal, Sailor Cosmos, and consequently Usagi herself, though this is only implied. The manga suggests this connection stems from a link between herself, Queen Serenity, and the birth of Princess Serenity long ago, but the exact events between them are left open to interpretation.