The Helm is obtained after killing a number monsters while wearing the relevant mask. The helm has similar benefits to the mask, but does not provide bonus XP, extra damage, or double drops. It does allow a slayer to force the choice of slayer task to this monster (daily or every 3 days depending on monster). It does provide free teleports to that monster (most provide 2 teleports daily). The mask's kill count carries over to the helm and continues to be tracked, up to 999,999 kills. Spirit of Battle is the only way to reset a helm back to a mask and re-enable the mask's benefits.