The Anti-Death Halo has only one purpose: to shield its user from the harmful attacks of Death. When active, a golden halo appears over the hero's head, and Death will instead flee. If the hero manages to get very close to Death, the effects of that particular Death will be reversed. To wit, using this on a Red Death will recover 100 health (this is the only way to increase health over the normal maximum) and a Black Death will steal experience points, easily granting one, sometimes two, experience levels. The Halo lasts for only a limited time.
A hero who defeats Skorne is granted this item as a permanent upgrade. Unlike other items (and with those versions of Legends that support inventory), the halo cannot be turned off and saved. It lasts for 60 seconds. Since there is only the Black Death, heroes need be concerned over their health, not experience level.