"Get ready to die, Sunset!" said Zhan Tiri, "You don't know what power you're dealing with!"
So Sunset Shimmer possessed Magic in the absence of Twilight. She was inexperienced in an element that didn't belong to her. The Element of Magic converted into Forgiveness, the one that truly belonged to her.
"No!" Sunset said, "No, no, no! I really thought that this would work! If only Twilight would just wake up!"
"You finished?" Zhan Tiri said, "It's such a shame it had to end this way. You just aren't as powerful without your precious princess."
"Zhan Tiri, wait!" Sunset said, "If there's some way to heal her, just tell me!"
"I'll tell you if you embrace your past and come with me," Zhan Tiri said.
Sunset Shimmer had a tough decision to make. Would she stay by her friends' sides and try to fight back and fail, or go with Zhan Tiri and have a chance to save Twilight?
She hesitated, but made up her mind. "I'll do it," she said.
"Sunset, no!" her friends cried.
Sunset Shimmer lowered her head. "It's what I must sacrifice to save all of you."
"Good," Zhan Tiri said, "Come with me. I'll tell you the way to save your friends."