Xalaphyre, the living Curse

As Xalaphyre enters the battlefield, choose a player. Xalaphyre has protection from all colors
of the chosen player's commander.
Extort (Whenever you cast a spell, you may pay {w/b}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you cast a spell, that targets the
chosen player or a permanent he or she controls, add {w} or {b} to you mana pool.