Thaddeus

Thaddeus was an angel who fell from Heaven to Earth due to Metatron's spell. Before his fall, he was a guard of Heaven's dungeons and its torturer. After he fell to Earth, he possessed the body of a popular pop singer known as Corey. He was killed by Gadreel under Metratron's orders.

Background
Thaddeus was once the guard of Heaven's dungeons and the responsible of torture the captive angels in there. He tortured Gadreel, by is betrayal, and also Abner, by unknown reasons.

Season 9
When Metatron completed his spell, all angels fell from Heaven, including Thaddeus. After that, he possessed Corey, a popular pop singer.

Before a concert, he entered in his room and found Gadreel, recognizing him. Thaddeus greeted him, calling him "friend" and Gadreel answered him they weren't friends. Gadreel accused Thaddeus for tortured him when he was imprisoned and he defended himself by saying he was just doing his job.

He then asked if Gadreel came from payback, saying he didn't have any problem with that. He tried to get his sword, but he discovered Gadreel already had it. The angel started to apologize, but Gadreel killed him.

Later, is revealed that Gadreel killed him under Metatron's orders, with the first saying that killing him was easy.