Age: Started at 14, Rock Bird at 15, Post-Rock Bird at 19, Post-Armageddon unknown
Height: 155 cm (5'1")
Weight: 40 kg (88 lbs)
O-Part: Jade Pendant
Ruby is a young treasure hunter researching the mysterious O-Part. She possesses extensive knowledge of ancient languages and aims to uncover the mystery surrounding her father Jack Crescent's death. Her father gave her a jade pendant, which turns out to be an S Rank O-Part with over 100 effects. Despite hardships, Ruby maintains a smile, believing that crying and running away solve nothing.
Ruby often worries about Jio and Ball during their battles against other O.P.Ts. She shares a strong bond with both, but seems to have deeper feelings for Jio, whom she has known longer. It is later revealed that Ruby is actually Sandalphon, the No. 10 Angel, and her "father" was not her real parent but a caretaker until her awakening as an angel. Nonetheless, she still considers him her surrogate father.
In the Olympia chapters, Ruby's soul is absorbed into Jio when Satan fatally wounds Cross. After a time skip, Jio and his friends infiltrate Stea's main base and manage to restore Ruby's soul to her body. She gains access to her angel powers, though they are not fully developed yet. Upon reuniting with her biological father, the leader of Zenom, he disowns her, leaving Ruby heartbroken.
When Shin begins collecting souls, Ruby sacrifices herself to save her father, sealing their pact with a pinky promise—a gesture she had once refused. Both are consumed by Shin and inserted into the Kaballah. Inside Shin, with the help of Jio, Cross, Zero, and Jack, they manage to warp Shin away from Earth, disappearing into space just as night falls.
As Sandalphon, the No. 10 Angel, Ruby can shrink and enlarge objects, including the Giant Ophan. This ability is only a fraction of her full potential according to Cross. Although not an O.P.T., she excels in treasure hunting and solving riddles. In recent chapters, she demonstrated enhanced strength and the ability to manipulate object sizes during a battle with one of the Four Warriors of Zenom.
