Ghosts of the Innocent

Multiple Ghosts of the Innocent effects are cumulative, and each will halve the damage, rounded down. For example, with three on the battlefield, 14 damage becomes 7, then 3, then finally 1, and only 1 damage would actually be dealt.

If both Ghosts of the Innocent and Furnace of Rath (which doubles damage) are on the battlefield, the controller of the permanent being dealt damage or the player being dealt damage can apply the effects in either order. This can matter if the original amount of damage is odd. For example, if a source would deal 3 damage, Ghosts of the Innocent would make it 1 damage, then Furnace of Rath would make it 2 damage, if the player chose to apply the effects in that order.

Half of 1 rounded down is 0. A source that would deal 1 damage won’t deal damage at all.