In the chaos, Eileen tries to take out Dagon with the legendary Colt, but she accidentally kills BMoL operative Renny Rawlings instead. This mistake becomes the final catalyst for the BMoL's war against American hunters.

"Supernatural" The British Invasion (TV Episode 2017) - IMDb

The heart of this episode is undoubtedly . Through chilling flashbacks to 1987, we learn he was forced to kill his best friend as a child at Kendrick’s Academy to prove his obedience to the BMoL Code.