|“||"Virtue is its own punishment."||”|
— Muriel's last words.
Muriel was among a group of angels who wanted no part in the angelic conflict, but since both sides were desperately rounding up angels, Muriel was forced into hiding.
When a seemingly helpless human prayed for help, Muriel answered, only to realize it was Castiel. She tried to walk away, but Castiel insisted she gave him information on the situation.
They gathered at a hotel room where Muriel explained the crisis going on. Suddenly, a follower of Malachi, Theo, and an unnamed angel, burst into the room and captured them both.
They were extensively tortured, with Theo revealing that he and his gang had been following Muriel, who he referred to as "cowardly". Theo then killed Muriel with an angel blade, despite Castiel's protests.
- Angel Blades - Muriel was stabbed to death with an angel blade by Theo.
- Primordial entities - Amara, God, Death and the Archangels could annihilate Muriel effortlessly.
- Muriel is known as the angel of emotions in lore.
- Muriel's actress Britt Irvin, previously portrayed a teenage girl in season 1 episode Hell House.