An Ability or Spell might require longer than the Caster's current Turn to cast. While Casting, the creature can't use Action Point(s). It requires the complete focus of the Caster to harness the Ability or Spell to completion. The Caster can drop this status at any time using End Casting.

Ritual Spells, cast a ritual, always require a default of Casting of 10 minutes.

Any Mana, or material components that are required, even including those that need to be consumed for the Spell or Ability, are required only when the Casting timer is complete. Casting essentially is the preparation for the Spell, Ability, or Ritual Spell.