The Shaman and Archmage use an identical mechanic but for the name. How does it work? Find out after the break.
Basically, you start with zero “High Magic” for the Archmage on the Order side between Serenity and Force, while starting with zero Gork or Mork for the Shaman on the Destruction side. Whenever you cast a healing spell, it builds the High Magic or Gork/Mork for the opposite type of spell that you cast. This can go up to five build-ups, but if you use a spell that has the opposite effect such as a damage or debuff spell, it uses the build-up of High Magic or Gork/Mork to augment the spell.
If you were casting damage spells and use a healing-type spell such as a heal over time, damage shield, resurrection, etc. it will use the build-up to augment those spells. Any spell that uses the build-up does not cause a point of High Magic or Gork/Mork to appear for the other type of spell. So, if you had four damage-type build-ups, and used a healing spell that was boosted by them, it just resets your build-up to zero for both sides.
For spells with a cast time, this in almost all cases reduces the time to cast by 20% per point of build-up, making it an instant spell at full power (yes, this does include even resurrection spells that could normally take up to six seconds on these particular classes). For spells without a cast time it affects them by 5% per point of build-up, for a total boost of 25%. For channeled spells, it also increases the effectiveness of the effect on a per-point basis.
The mechanic works very nicely in actual gameplay. While you cannot opt to “store” your build-up if you use a spell that would normally consume it, every single spell you cast uses this mechanic except for pure long-duration buffs (such as a resistance buff that lasts an hour). Short-duration buffs will count for this though as well. Even instant-cast spells will build up points for the mechanics of High Magic and Gork/Mork. You’ll find yourself trying to store up points and balancing what spells you cast to plan ahead. You might cast a bunch of damage spells quickly when you think you might want a quick, large instant heal with five points built, or a resurrection, expecting to need it in the next several seconds. Likewise you might do some quick healing so that you can cast a very powerful channeled nuke when a target is being damaged, to help be ready for when the group is trying to finish him off.