Nightmares are constructed when Kurami activates Kamimusuhi, while only needing to drift those bloody eyes once at the victim, and have locked it for at the very least four seconds. Within a fragment of a millisecond Kamimusuhi throws the victims into a world of darkness, crawling into their mind with those dark, cruel nightmares to unlock those deepest and darkest memories, and use these to birth them into a new illusionary world. Whereas time and torture is the key of Tsukuyomi, Kamimusuhi builds an entire world to break the mind of the trapped apart, to recall their own memories in a realistic way. Feeding them with lies after these victims are broken minded and extract the necessarily information would Kurami require so.