Nithael is one of angel stationed in Earth after The Darkness rising.
At some point, he tracked if Lucifer presence detected in a park, only to find if he is inside the Castiel body. When he tried to killed him with an angel blade, Lucifer tell him to stop it because he claimed his coming is for saving the world from the Darkness as he is only the hope to beat her. He also commented why Nithael also want to take a job that make he leaved the original post, making his original task abandoned. However, Nithael doesn't believe him and trying to kill Lucifer and saying if the Darkness is invincible and cannot be destroyed. Nithael action make Lucifer to molecularly combusted him, killing him.
- Nithael is angel of rejuvenation and eternal youth. In lore, the angel helps people to attain the mercy of God and longevity. He protects the heads of state, presidents, monarchs, princes and all the people who devote their lives to spirituality and charity. He favours the continuation and legitimacy of families and business stability. He also helps people who need help from individuals in high places and provides a quiet and safe existence.
- Nithael name means "God, the king of heaven". It also ironic, as he (in Supernatural-verse) was an lesser angel.