When your Hero reaches level 4, each time they successfully complete a non-Arena level 4 or level 5 scenario, as well as at various other times during the game, your Hero may gain an Inspiration gem . Each Hero may have up to 5 Inspiration gems at a time. If your Hero would gain a sixth Inspiration gem, gain an Achievement gem instead.
An Inspiration gem may be discarded to roll 2 more on any attack or active ability check, or 2 more on any reactive ability check. You must decide to discard the Inspiration gem before rolling any dice. You may only discard one Inspiration gem before each such roll.
In addition, at level 4 your Hero gains actions that cost an Inspiration gem to perform. You may not perform the action if you do not have an Inspiration gem. You may still perform the rethink action instead.