Dal link di training grounds che hai messo:
Cita:
6/15/2010: Training Grounds can reduce the amount you pay for a creature's activated ability cost that includes 
. For example, Drana, Kalastria Bloodchief has an activated ability that costs {B}{B}. If you control Training Grounds and you activate the ability with X equal to 5, you'll have to pay only 
{B}{B}. This is true even if the ability states that must be paid with a certain color of mana, as Crimson Hellkite's ability does.
. For example, Drana, Kalastria Bloodchief has an activated ability that costs {B}{B}. If you control Training Grounds and you activate the ability with X equal to 5, you'll have to pay only {B}{B}. This is true even if the ability states that must be paid with a certain color of mana, as Crimson Hellkite's ability does.