The Serpent Heads devour hearts and assist in executions. In the first game, they are used as a visual to show the player that Jackie is currently using The Darkness, they have a Dark Energy meter shown at the sides of their bodies that gets filled when the heads "absorb" the darkness around them as long as they aren't exposed to direct light, this causes them to flinch (eventually hiding) and to lose Dark Energy. They are the key to using the Darkness Powers, abilities unlocked through the game consuming the hearts of certain enemies, all of them use the Dark Energy to work, these include a Demon Arm, which impales enemies, a Black Hole that absorbs and kills all the enemies in range, Darkness Guns and even controlling one of the Serpent Heads, making it climb walls and attack opponents r