Triggering a Psionic Power
MAC scores have been assigned to all psionic powers. The user rolls against his MTHACO score, as if he was attacking psychically. If he scores an MAC equal to or under the MAC of the power that he wishes to trigger, then the power is successful, and the user must pay the full psp cost, even if the target makes its saving throw. If he fails the MTHACO roll, then the power fails, and the user pays a lesser secondary cost. For example, Ayani tries to trigger her truthear ability. Truthear is listed MAC 10, psp cost 3/1. This means that Ayani, with her 18 MTHACO, must roll an 8 or higher to successfully use Truthear. If she succeeds, then she can pay 3 psp per round to maintain the power, or only pay 3 psp and drop the power after one round. If she fails the MTHACO roll, then she only spends 1 psp, and may attempt again.
PSP CostPSP costs have been assigned to all psionic powers. Unless stated otherwise, the cost applies at initiation of the power, and every round thereafter that the power is maintained. If the power fails, the psp cost is reduced to 1, unless otherwise noted.
Psychic ContestsWhen two mindbenders use psionics on the same object (for example, both attempt Telekinesis on the same object), a psychic contest results. The mindbenders roll MTHACO checks; the lowest successful die is the winner. If one user succeeds and the other one fails the check, the successful mindbender wins the contest. If both rolls fail, none of the powers succeed.
If both mindbenders succeed and the dies are equal, then a psychic lock occurs. In a psychic lock, neither competing character wins the psychic character that round. To resolve the contest, both characters must pay the power cost and engage in an other round of contest. If either character fails to pay the cost, that character suffers a psychic backlash and looses 4d4 psp immediately.
Critical Successes and Fumbles
Under House Rules, Critical Successes and Fumbles never occur on a roll of a 1 or 20. Braxopinion: the 20/1 rules are simply absurd. Since 1 is always a failure, and a 20 is always a success, it makes no sense to make these rolls critical, since this would mean that for high level characters with easy tasks, all failures would be critical, and for low-level characters with difficult tasks, all successes would be fumbles.
The C&T approach (critical hit on a 18-20 if the roll is at least 4 greater than what is required to hit) results in more believable patterns of critical success, but this requires too much game-slowing arithmetic. House Rules apply a similar principle, without slowing the game down:
Fumbles are provided for a number of powers; the DM may also create individual critical successes if desired, or rule that the critically successful power only costs 1 psp on the round of initiation.
A roll of 5, 10, or 15 always results in a critical success or a fumble -- depending on whether the roll succeeded or failed.