A teammate is a player who shares a victory condition with you (you both win if you work together to remove another player or players)
This includes , and Ice Age/Alliances , Mirage/Visions/Weatherlight , Tempest/Stronghold/Exodus , Urza's Saga/Urza's Legacy/Urza's Destiny , Mercadian Masques/Nemesis/Prophecy , Invasion/Planeshift/Apocalypse , Odyssey/Torment/Judgment , Onslaught/Legions/Scourge Mirrodin/Darksteel/Fifth Dawn and does not include base sets or pre-Ice Age sets
You can target an untapped permanent for untapping, but no cards you have that say when a permanent you control becomes untapped would trigger
Unless youve delved deep into the late-game, that four mana is likely to be a huge stumbling block, removing an opponents threat before it ever hits the field
This makes the legendary champion a fantastic card to add to any Steel deck