Okay, I have finalized the system for Essence use in Novarium. It is kinda like nitro fuel for magic.
As a quick recap, in Novarium you combine two elements to get a score, similar to an attribute score, based on the sum of the two elements. So if you have a Strike of 5 and a Fire of 10, you have a Strike-Fire of 15 (this should not be hard to figure out). Depending on the effect you are going for, you roll a number of 10-sided dice. You are trying to roll under your score. If you fail by a margin less than your highest die result, the spell still works but you lose 1 Willpower trying to force it to happen. (anyone familiar with Ars Magic should see some parallels here).
Using Essence is like popping a little magic candy to really pump up the flow of magic.
When you use Essence, you must specify how many points you are using BEFORE moving forward at all. You only get one chance, make the call. Once this decision is made, the Essence objects disintegrate and there is no going back.
Next, you roll 1d6 per point of Essence used. This many DICE are subtracted from the difficulty of the casting. So if you were rolling 3 dice and you roll 1d6 to get a 2, the difficulty is now reduced to 1 die.
But I can hear you thinking... what happens if you roll a 6? This is called Overload.
Now things are getting out of hand. You may not be able to control magical energy in this quantity. No matter what, those extra dice have to go somewhere. There are three dice worth of magical energy that will be spent somehow, someway. The only question is who will decide how it is spent, you or the Architect (GM).
You have to take the extra dice and roll them against your Stability attribute to see if you can control it (the Arcana skill can be added if you have it). If you succeed on the roll, you control the Overload. If you fail the roll, the Architect controls the Overload.
So in this example, you would have three overload. So that is three 10-sided dice against an attribute generated by 3d6, odds are good that you are going to fail this roll. Lets say you fail. You can't control the spell.
You cannot take the difficulty negative. So in order for the Essence to be used, you have to increase the power of the magical effects in play. The power of the spell is increased until the energy is used.
Lets say you were targeting an individual with the fireball. The Architect tells you that now you are targeting the whole room (+1 difficulty), and the fire is hotter (+1 difficulty), and it burns out over a longer time period (+1 difficulty).
BLAMMO!
And we are just talking about fire.
Imagine the havoc that overload will play with your time manipulation spells, your healing spells, etc.
Oh joy....