Awakening: Katsumi was the last of the Quartet sisters to transformed. Her time came a week before her 17th birthday. On a Saturday during a strong storm, Katsumi tagged along to the mall with Usagi and Chieri. The trio just arrived when an explosion sounded near the entrance. A cluster of aliens announced themselves and immediately went to attack Usagi. In the flash, Chieri transformed expertly while Usagi struggled a bit to keep up since it was her first battle. Together they got to work on the aliens while Katsumi made herself useful by helping the civilians nearby. One alien broke off from the cluster baring its claws to attack a young child. Katsumi used her body to block the monster but no hit came. A smouldering shield appeared in front of her and on her left ring finger was her new transformation ring. It was like her sisters' in a way except hers was a compete ring with no gap in the middle. It was silver and dainty ring with one side having her dark red pearl stretching to meet in the middle of the ring with another pearl that was iridescent and shimmered her sisters' colors depending on the lighting. Katsumi assumed that her ring is supposed to symbolize her power over the hearth with her transformation item representing her family. Katsumi became Sailor Vesta, blasting the alien with a face full of hot ash and joined Chieri and Usagi defeat the rest. After the battle, they treated themselves for ice cream as a pick-me-up.