Possessed
"Erela! Stop!" Sam shouted. Dean and Cas came running over to them and were confused by what they saw. Erela had Sam pinned to a tree, holding him by his neck. Her wings were wrapped around them, shielding them from view.
"What are you doing?" Dean demanded, stepping toward Erela and Sam.
"Dean, wait. Something is wrong," Castiel warned as Dean went to grab Erela's free arm. She turned to look at the angel with an evil smirk that did not belong to her.
"Look at you. You think you're so smart," Erela sneered.
"Erela… What…?" Dean said.
"Oh, shut up Dean," Erela replied, flicking her hand and sending him flying against a tree.
"Dean!" Sam choked. Erela turned to face him again and her eyes were pitch black. Suddenly she let Sam go and fell to her knees, choking and coughing, and she wrapped her wings around herself.
"Sam. Help me. I'm fighting it," Erela pleaded.
"Yeah, sure," Dean replied, doubtful. Erela looked up at Sam with fear in her eyes.
"Agh! Dammit!" she shouted, gripping her chest. Sam helped her into a standing position and leaned her against a tree.
"We have to get this demon out of you," Sam told her.
"No. Sam, you can't. You can't. It's intertwined with my grace and my soul. Pulling the demon out might kill me. It's ripping me apart as is," Erela explained.
"But, I don't- There has to be another way," Sam tried.
"Sam, she's right. You have to use the knife. She'll die either way and that way is just easier on her. I'm sorry," Castiel said gently.
"Sam… Please… Just make this stop," Erela begged. She was crying. "It's getting harder and harder to hold on to it and I don't want it to hurt you. It wants to do terrible things to all of you." Sam walked over to Dean and took Ruby's knife from him. He then walked back over to Erela and held her close.
"I'm sorry, Erela. I really am," Sam told her. He was crying too. He tilted her chin up and kissed her. Erela kissed back. Sam took a deep breath and plunged the knife into her back, up to the hilt. Erela gasped and made a strangled cry as the demon inside her died and so did she. Her wings twitched one last time, then her body went limp and slumped against Sam.