Enigma Tree was a member of House Arpexia.
She adopted Earth as her home planet, spending some of her time in the 1960s. She noticed that Earth had begun to switch between three different timelines and left the planet in her timeship to examine them. After a trip to her favourite resort planet, she resolved to sort things out.
After Violet told her Trudiode had been captured by the Jalaxians, Enigma led the effort to free her friends, rescuing Violet and Judy Collins before hacking into the Jalaxian's control centre and fixing the planet's history.
She had a "complicated" past with Yardley James. (PROSE: Judy's War)
Behind the scenes
Enigma Tree also appears in Rachel Redhead's self-published novels The Enigma Variations and The Inferior Comedy.