Lyric discussion by GuyCarlPeterson 

Cover art for Moonlight Equilibrium lyrics by Black Dahlia Murder, The

At first I just thought this song was just about werewolves too but the more I listened to it the more I started thinking it was about another Castlevania game. Lords Of Shadows. There are subtle things in it and obvious stuff like all the werewolf talk but then the part that really made me think it could be about that game is:

That very eve the devil cameth, And his will did force thine idle hands. Open this heart of molten darkness, Floweth foul rivers of the damned.

SPOILERS FOR THE GAME

There is a part in the game where the main character goes to sleep one night and ends up being forced to kill a companion. Throughout most of the game he is being guided by his mentor who at the end of the game turns out to be Lucifer.