Tessa

Tessa was once a young girl that had gone into the hospital to get her appendix taken out. The surgery, unfortunately, goes wrong and her body is possessed by a reaper in order to convince Dean to move on following the car accident that he and Sam were in. Unknown to Dean, Tessa is actually working with Yellow-Eyes to get his soul and send him to hell. Tessa tells Dean that death is nothing to fear and he would be dying an honorable death, a heros death. He angrily retorts that there's nothing peaceful or right about any of this. He eventually falls into her trap by agreeing to move on after she points out that if he doesn't, he'll turn into a spirit, an angry spirit that his family would have to hunt down sooner or later. Not wanting to put his family through that, Dean agrees to move on with her.