Cha'Qi'Thl's Theorem

Once per battle, in any phase, you can use Cha'Qi'Thl's Theorem if a model with this Relic is on the battlefield. If you do, select one Stratagem. Until the end of the phase or until after that Stratagem is used by the model with this Relic's controlling player (whichever comes sooner), reduce the Command Point cost of that Stratagem to 0.