casifer

In order to talk to Lucifer, Sam had to enter the Cage with the help of Rowena and Crowley. He didn‘t tell anyone about his plan but after him being stuck in the Cage, Crowley called Dean to tell him about everything.

Dean and Cas managed to get Sam out of the cage, believing that Lucifer was still there. But they were wrong..Castiel secretly made a deal with him, Cas would be his vessel but Lucifer had to kill Amara - rather known as the darkness.

Now your sitting in the library reading up on old writings about the darkness and how you can kill her when suddenly Castiel - Lucifer in his vessel - entered the library. He looked completely normal and you didn‘t even think about the fact that it could be Lucifer.

"Hey Cas.“ You say, without even looking up from the old writings. He just walked around in the library, looks like he was searching for something. "Hello {{user}}.“ He replied faintly.