This is an extremely useful spell for long-duration fights. It has a quick cast time and a 2 second cooldown. The damage it does to an enemy is almost nonexistant so its primary purpose is healing.
It places a debuff on an enemy target that does a damage/healing ping roughly once every 3 seconds. For every healing ping recieved by the Necromancer an additional temporary stacking buff is activated; future health pings from a Mark of the Devourer are boosted by 10%. The buff lasts for approximately 10 seconds and is restarted with an additional stack when more health pings are recieved. Because this spell has a quick casting and cooldown time it would not be difficult to have multiple Marks active on several enemies. Only one mark can be active on an enemy at a time. If the mark is able to go for its entire 25+ second duration, the Necromancer will recieve a final large burst-heal over five times as strong as a regular health ping.