Ability Counter

Ability counters are counters which monster can remove to activate certain effects. The number of counters needed to be removed varies not only from monster to monster but sometimes even on one card with multiple effects. Occasionally counters may only be removed by fulfilling another condition, or may need an additional cost to activate the effect. Generally, ability counters are replenished eac stanby phase of the monster's owner and each monster with such countes can carry a maximum of four.

They basically are my way of representing 'mana' or 'energy.'