in its mana cost, X is 0 for the purpose of determining its mana value.A low mana curve changes the way Dark Confidant plays. Each upkeep supplies the top card of your library and costs life equal to that card's mana value. Lands cost no life, inexpensive interaction costs little, and a deck full of efficient spells can turn the two-mana creature into a steady stream of resources.
High-cost cards create a different risk even when you rarely intend to cast them normally. Their mana value still determines the life loss. Sensei's Divining Top and other library-selection effects can help arrange a manageable reveal, but the deck should not need another permanent just to make Confidant survivable. Evaluate the entire curve, including expensive finishers and alternate-cost spells, before adding it.
Putting the revealed card into your hand is not drawing it, so draw-specific restrictions do not stop that part of the ability. The reveal does give opponents information, and the trigger is mandatory once it resolves. A sacrifice outlet can help remove Confidant before a later upkeep when your life total can no longer support the engine, although sacrificing it after a trigger is already on the stack does not erase that trigger. It is strongest in aggressive or interactive black decks that can spend the extra cards quickly and finish the game before repeated life loss becomes the larger problem.
