Tasigur, the Golden Fang {5}{B}

Notes and Rules Information for Tasigur, the Golden Fang:

• Tasigur, the Golden Fang is banned as a commander in Duel Commander format, but it may be part of your deck. (Scryfall note, 2015-01-19)
• The chosen opponent can choose any nonland card in your graveyard, not just one of the cards that was just put there. The player must choose a nonland card if there’s one in your graveyard. (2014-11-24)
• You exile cards from your graveyard at the same time you pay the spell’s cost. Exiling a card this way is simply another way to pay that cost. (2014-11-24)
• Delve doesn’t change a spell’s mana cost or converted mana cost. For example, the converted mana cost of Tasigur’s Cruelty (with mana cost {5}{B}) is 6 even if you exile three cards to cast it. (2014-11-24)

• The last ability doesn’t target any card or player. You choose an opponent as the ability resolves and that player chooses a nonland card. (2014-11-24)
• You can’t exile more cards than the generic mana requirement of a spell with delve. For example, you can’t exile more than five cards from your graveyard to cast Tasigur’s Cruelty. (2014-11-24)
• Because delve isn’t an alternative cost, it can be used in conjunction with alternative costs. (2014-11-24)
• You can’t exile cards to pay for the colored mana requirements of a spell with delve. (2014-11-24)