Guardian Seraph | Magic: The Gathering
Formats Guardian Seraph is Legal in
Official Oracle Text for Guardian Seraph
If a source an opponent controls would deal damage to you, prevent 1 of that damage.
Official Rulings for Guardian Seraph
10/1/2009 : Spells and permanents have controllers, but cards that aren't on the stack or the battlefield don't. If a source without a controller (such as a cycled Jund Sojourners, for example) would deal damage to you, 1 of that damage is prevented if an opponent owns that source.
10/1/2009 : The effects from multiple Guardian Seraphs are cumulative.