Mara was the last She-Ra before Adora, according to Light Hope. Light Hope tells Adora that Mara struggled to separate her personal attachments from her duty, causing her to be unable to fully understand the scope of her powers, which ultimately resulted in her mind snapping. She did something to endanger the entire planet and wound up breaking the She-Ra line for a thousand years before Adora. She was first mentioned in episode 3, Razz, when Madame Razz thought Adora was the old warrior.
Adora is the current bearer of the position of She-Ra. She was the Force Captain of the Horde. Later, she discovers that her faction is evil and can no longer stand by their deeds. She leaves the Fright Zone to join the Rebellion and co-founds the Princess Alliance with her friend Glimmer.