Elita-One

Elita-One, also known as Elita Monon or formerly E1, is a character and major protagonist in the Transformers franchise. She is the sister of Arcee and Chromia, as well as the leader of the female Autobots, Optimus Prime's love interest and Nancy Witwicky and Mikaela Banes' mother figure and mentor. She is the leader of the Female Autobot within the franchise. 
She is meant to serve as Optimus Prime's female counterpart and love interest in several adaptations.