(I didn't have time to write this part out with my earlier message)Actually you didn't misinterpret, the Treabor did. He calls Cole a "Zarpathos-scion" because no one outside of the House of Zarpathos has ever weiled the Stone, that is, until Cole. The Treabor recognized the psionic energy signature del Tigre had as being the same as that of Tatriana Zarpathos, a mentalist who apparently battled the entity in a similar situation in the distant past. He assumes that since Cole is using the stone (which generated the energy signature) then he must be a Zarpathos. It's actually a misnomer.
The Stone of Zarpathos can actually be used by anyone. Cole offered it to Sailor Zeo to make her attackers pay. He also shared using it with Iris so he could have a psionic anchor without the assistance of another telepath as none were available at that point.
However it has been assumed that only members of that family can use it, as those who defeated/killed the Mentalists could never use the stone.
The true reason it never worked for them is because the no one outside of the family knew the pouch was needed to recharge it. The pouch looks ordinary enough that no one ever suspected that its actually a power source for the Stone.
Any true member of the House of Zarpathos would have had real psionic abilities (they are a family of mentalists, after all), for them the Stone would act as an amplifier. Cole, on the other hand, was no true psionic; but the Stone grants him mental powers on roughly their level. The Treabor and Venger regard Cole with the Stone as being a 'novice' because his abilities are not as powerful as they would be if he had always been an innate Mentalist using the Stone.
