Ability mechanics

Activated
Activated spells have an original mana cost in order to cast it but nothing further. After the initial cast, the mana cost is drained and the desired effect is achieved.

Sustained
Sustained spells do not have a cost but instead have an upkeep. This upkeep is taken from your max mana instead of the mana you have available. If activated during combat this means you could take advantage of a larger pool of mana until you activate the sustained spell. Additionally, a cumulative fatigue penalty is gained for as long as the spell is kept active. Fatigue increases the mana cost of subsequent spells by a certain percentage.

Passive
Passive spells are neither cast nor activated, but instead affect the properties of some action that the mage performs.