The Chochtic was a menace to the people of Pran in the Age of Everdunes. That was true even during the time while Atrus explored Channelwood and while revisiting Everdunes he feared that the Chochtic threatened the people's very survival. The Chochtic probably caused the death of Pran.
Only one vague reference is made to the Chochtic, deliberately creating a sense of mystery about its/their nature, leaving it open to speculation.
Context might suggest that Chochtic was a hostile tribe that raided or had a war with the people of Pran, or that they were some wild creatures native to Everdunes. It is also possible that the Chochtic was a form of virus or disease.