I take it you are saying darkness attacks from within. While this may be a proven tactic, it is still a cowardice one. As the darkness does this, so do nightmares. Nightmares too become a part of you, but they are not cowards like darkness. Nightmares are the children of the night. Nightmares haunt your dreams, as well as come back during the day, forever persistent. Nightmare's deliver fear, enough in some cases to diminish a mans sanity enough to kill. Ghost, spirits, and demons may lurk in the dark, but they attack as nightmares. Nightmares feed off of the fears of others. If even the smallest sliver of fear is present, nightmares will be there, ready to claim their next victim. So watch you back, nightmares attack randomly, and it could be you whom they come after next.