6.  Spells, Abilities, and Effects

606.  Loyalty Abilities

606.1  Some activated abilities are loyalty abilities, which are subject to special rules.

606.2  An activated ability with a loyalty symbol in its cost is a loyalty ability. Normally, only planeswalkers have loyalty abilities.

606.3  A player may activate a loyalty ability of a permanent he or she controls any time he or she has priority and the stack is empty during a main phase of his or her turn, but only if no player has previously activated a loyalty ability of that permanent that turn.

606.4  The cost to activate a loyalty ability of a permanent is to put on or remove from that permanent a certain number of loyalty counters, as shown by the loyalty symbol in the ability’s cost.

606.5  A loyalty ability with a negative loyalty cost can’t be activated unless the permanent has at least that many loyalty counters on it.