Evil Sally was born in the alternate reality of Evil Mobius, a world of anarchy and crime where gangs and thugs ruled over a wasteland of their own making : this version of Mobius evolved as the ultimate conclusion of what would of happened had Mobius never truly gained any form of monarchy or government beyond that of opportunist warlords, unlike Dark Mobius it was completely without law and never had any conflicts with Overlanders, who had went extinct long before Mobians became the dominant species of Mobius.
Indeed in this reality Mobians never contacted other worlds and warred among themselves, with Evil Sally joining Evil Sonic's gang out of both necessity and a desire to someday usurp him - the pair engaged in a romantic relationship but due to the twisted nature of Evil Mobius this relationship was abusive on both ends, a mockery of the very concept of romance.
When Evil Sonic entered mainstream Mobius he brought Evil Sally and his gang with him, the criminals soon went on a rampage and enjoyed the prospect of an entire new multiverse to "play" with, having never dreamed of life outside their own world - indeed Evil Sally found the concept of beating her alternate counterpart to be thrilling and gladly engaged in physical conflict with mainstream Sally, though she was infuriated at being outclassed by Sally, who was a more experienced and disciplined fighter.
After Super Evil Sonic was defeated and sent back to Evil Mobius via a Warp Ring Evil Sally managed to evade capture and tried to start her own gang on Mobius before being captured by Mobian authorities, before she could stand trial for her crimes she was broken free by Evil Sonic's gang and fled back to Evil Mobius.
Ever since then Evil Sally has been a recurring enemy to Mobius and its allies, especially prone to showing up in the rogue galleries of Silver, Team Chaotix and Sonic.
- chaos-absorption (Evil Sally can absorb chaos-energy from relics such as Chaos Emeralds, the Master Emerald or Power Rings and when she gains enough energy she can enter a super-transformation stage.)
- enhanced-intellect (Evil Sally is very cunning and intelligent with a particular talent for criminal gain, she suffers from impulsive behaviors and an inability to understand the concepts of "good", she is also easily angered and frustrated when things don't go her own way.)
- combat-mastery (Evil Sally is a vicious combatant who has engaged in numerous styles of fighting but lacks discipline or experience in most of them, unable to focus for long periods of time and resorting to cheap tactics or reckless moves, Sally commented that Evil Sally (and most other Evil Mobians) fought much like schoolyard bullies, always taking advantage of weakness but rarely taking the time to improve their own techniques.)
- authority (Evil Sally has authority over most members of the Evil Sonic gang by simple virtue of being slightly tougher and smarter than them, thus she can bully or harass them into doing as she desires - by their nature most under her control inevitably betray her when they can, which she sees as natural (indeed it is a common trait of Evil Mobians).)
- despite her name Evil Sally is, ironically, one of the least dangerous alternate versions of Sally Acorn : the others being Alicia Acorn and Metallix (both of whom are considered among the most evil villains in the entire Cosmic Crusade franchise).
- Evil Sally, like all residents of Evil Mobius, has extreme difficulty understanding "good" and thus has shown genuine confusion over some of the actions of her opponents - such as when they aid fallen team-mates or show her mercy.. she has admitted that such acts frustrate her, suggesting that deep down she wants to learn about "good" but is virtually incapable of doing so due to the nature of her reality.
- just like Evil Sonic her seeming inability to understand "good" puts her moral agency in doubt, thus she is not comparable to characters such as Robotnik - who have shown to understand the concepts of "good" and outright rejected them in favor of wrong-doing.