0 Health Glitch is a collection of phenomenons of an unit to be able to enter into play with initial 0 health. (can or cannot be healed to increase, see below) The first pheonemon is that an unit with initial health 1, gets diseased and then died and animated (mostly in the same attack but artifacts prolonging life would not prevent the glitch) As usual the unit would have maximum health and attack decreased by 1, but it makes the unit to have initial health of 0 on entering play. All ways to revive an unit other than animated (including reanimate) will fully cure the unit.