From the Web Addendum vol. II:
Gnosis is the supernatural presence possessed by a certain individual or group. It measures the importance of that groups supernatural presence in the world and the transcendence of its actions in the future. The higher the Gnosis, the greater things the group is destined to do and the more difficult it will be for it to fail. Gnosis is reflected by a number of points both sides have available to them to change the result of their rolls. Every Turn each player receives one Gnosis point for each 100 levels of encounter in the game. So, in a level 300 scenario each side will have 3 Gnosis points per Turn. At the start of each Recovery Phase the Players renew all Gnosis Points they used in the previous Turn. The best way to represent Gnosis is with Action markers. When a Player uses a Gnosis point, the counter is removed to show the use. A player can use a Gnosis point to improve ANY kind of roll. The player simply rolls an extra die and chooses the best result. This ability can be used in all rolls in the game: Attack, Defense, Initiative, Seek, Resistance rolls… and even to avoid the consequences of negative States like Doom. Anything that is decided by chance can be affected by Gnosis. When for an Action or Special abilities causes two or more dice to be rolled, Gnosis adds another die to the roll. For example, a Character that Charges and uses a Gnosis point would roll 3 dice for the attack; 2 from the Charge itself and one due to the Gnosis.
The use of Gnosis points always has to be declared before rolling the dice, and only one point can be spent per roll, no matter how many the Player has.