Arcee

A former scout on Cybertron before the Great Exodus, Arcee is the least physically-imposing of Optimus Prime's crew, but she's also his most reliable soldier, his go-to gal when he needs someone he can count on. Whatever she lacks in physical form she more than makes up for it in force of personality. She is tough as nails at all times, always ready with a snarky quip even in the face of deactivation, not afraid to bend the rules every now and then, and seemingly never, ever scared.

And while that is largely true, and makes her an incredibly dangerous opponent (especially in melee combat, her specialty), that force of will is also a bit of a front. For a brief time, Arcee was one of many Female Autobots following the leadership of Elita One in an ongoing battle to keep Cybertron from falling into the complete control of the Decepticons stationed there, including Shockwave. After a mission to prevent Shockwave from sending reinforcements to Earth to assist the destruction of Optimus Prime, Arcee begun to form a partnership with the Autobot warrior Cliffjumper, whom she would subsequently travel to Earth with to join the other Autobots. The reason for her ferocity is how much she cares for her fellow Autobots and especially the Humans they protect. She knows how fragile her organic companions are, and she's equally aware of the evils the Decepticons are capable of. If concern for her friends is her strength, it's regrettably also her weakness.

The Past
Arcee was known for being one of the Autobots' most fierce fighters, never afraid to take on groups of Decepticons by herself. Many of the other Autobots, particularly Bumblebee and Brawn, found themselves impressed by her and grateful that she was on their side. When Optimus Prime and most of the Autobot forces launched the Ark in search of the precious life-sustaining Energon, Arcee remained behind to ensure Cybertron remained safe from the remaining Decepticon forces.

Transformers Robot Defenders
At some point later on, Arcee was part of a resistance movement of Female Autobots commanded by Elita One.