also known as: Varlet

Killer initially works under Dream as one of his guards. Dream picked him up from his AU to remove its source of negativity, but found him volatile and difficult to control. Dream slowly increased his control over Killer's soul until he was almost unrecognisable; a completely emotionless drone only capable of following Dream or Strike's orders.

Dream had Killer stationed to watch over Nightmare's chambers while he was in his coma. Unfortunately for Dream, with sufficient distance from the source of the control over his soul and close proximity to Nightmare, eventually the spell broke. The resulting burst of negativity from Killer, now experiencing all of emotions he was neither capable of understanding or processing over his captivity, was enough to give Nightmare the strength to wake up. Recognizing he awoke in Dream's palace, Nightmare was quick to escape with him.

Their relationship at first was tense. Killer couldn't help but see Dream in Nightmare, and didn't want to be trapped in another situation he can't escape. Unfortunately sticking with Nightmare was his only option, as Dream was hunting him across the multiverse in an attempt to get his brother back.

They have since become close companions. Nightmare is glad to have someone on his side in this seemingly impossible conflict, even if he is concerned about the state of Killer's soul. Killer still struggles with depersonalization and delusions, occasionally believing he's still under Dream or the player's control. Nightmare helps him as best he can during these episodes, in addition to stopping him when he goes too far in a fight.