Sage is Dr. Eggman's AI daughter, and this obviously makes her a member of the Robotnik Family.
History[]
Sage was created when Dr. Eggman did something inappropriate to a computer, which caused Sage to be born. When Kanna, Dr. Eggman's wife, came back from vacation, she thought that her husband was cheating on her, but Dr. Eggman explained that he- okay fuck it, all you need to know is that Dr. Eggman and Kanna are still married. Sage lives with Dr. Eggman and Kanna, and she also lives with her two older brothers named Mario and Luigi.
During the events of Sonic Frontiers, Sage meets Sonic and tells him to leave. Whenever Sonic asks "Why?", Sage says "You cannot understand.", and this happens OVER 9000 times. Sage gets bored and grabs an AK-47, but Sonic and Tails defeat her with the power of friendship. Suddenly, the Moon tries getting revenge on Dr. Eggman, who pissed on the Moon. Sage then teams up Sonic and they nuke the Moon, but then Sage DIES... but she's an AI, so she lives. After that, Sage goes back to being a villain, and her evil plan is to replace entertainment with AI generated content.
Later, Dr. Eggman asks Sage to give him nuclear launch codes, but the codes don't work because Sage didn't want her father to nuke the UnWorld. How nice of her! However, Sage is evil, so she kills people for whining about their voices being copied by AI. Caillou tries calling the UnPolice to arrest Sage, but since Sage is an AI, the UnPolice don't arrest Sage, who kills Caillou for telling on her.