Harness Ability skill

Streams of raw mana flow all over Elanthia in various forms, and this mana can be tapped into by a mage and used to fuel his spells. In fact, most magic must be fueled by mana, or it simply won't work.

Your Harness skill represents your ability at manipulating this raw mana, which can often involve some tricky maneuvering by the harnessing mage. Harnessing is just that; the mage taps into these flowing lines of mana and attempts to use their power for his own means. Obviously, you can not actually remove the mana from the streams, or surely Elanthia would be barren of mana by now -- all you can really do is try to keep a regular flow of it channeling through your system for as long as your skill allows.

As such, your HARNESS (or MANA) represents your current connection to these mana streams. Harnessing mana is a demanding and strenuous process, and requires that the mage attune himself to the mana he has been trained to use. Casting too many spells or harnessing too much mana weakens this attunement, making it harder and harder for the mage to channel more mana without pausing to let his attunement restore itself.

It may be easier to think of this as your 'current mana sensitivity,' though that is not an entirely accurate way of looking at this process. It would be more accurate to think of Harness as your current ability to plug yourself into those flowing streams of mana.

Wait -- If mana can't be held, then what's going on in group harnessing?

When others in the caster's group harness mana, it does help the caster but does not actually contribute that mana to the spell. The group's mana helps by reducing the natural resistance mana has to being harnessed -- a single mage harnessing mana will have a more difficult time than if his comrades are 'softening' the surrounding streams with their own efforts.

Upon casting, that helpful group energy dissipates, making the caster's own use of mana as efficient as if he'd harnessed more than he really did. However, since mana types are not truly compatiable, this is also why like-mana is more efficient than mismatched mana in group harnessing efforts.

It is assumed that HARNESS SHARE OFF/ON simulates 'proximity' to the casting mage -- someone standing away from him would not be contributing to the effort of reducing natural mana resistance nor helping efficiency.

Training

In general, Harness skill is learned best from casting spells at large amounts of mana, with full preparation. Raw harnessing and charging cambrinth also provide modest experience.