Jake Sisko possessed by a Kosst Amojan in 2374
Kosst Amojan was another name for the non-corporeal entities known as the Pah-wraiths. In 2374, one of the Kosst Amojan inhabited the body of Jake Sisko in order to bring forth the Reckoning. The entity was driven out after Kai Winn Adami flooded the station with chroniton radiation. (DS9: "The Reckoning")
See also
Background
Ambiguity exists as to whether Kosst Amojan is an individual or another name for the Pah-wraiths. Kai Winn refers to it in an ancient prophecy as an individual in "The Reckoning", however in "Shadows and Symbols" the Sarah Prophet refers to the Pah-wraiths which were defeated in that episode as the Kosst Amojan. Furthermore, in the final episodes of the series, Kai Winn herself refers to the Pah-wraiths in the Fire Caves as the Kosst Amojan. It is possible that the individual Kosst Amojan (whose whereabouts remain unknown) entered the wormhole with the Pah-wraith at the end of "Tears of the Prophets" and subsequently both were destroyed. The prophecies as Winn knew them in "The Reckoning" were possibly misinterpreted, just as they were in "Destiny" regarding the "three vipers", and the Kosst Amojan is in fact the Prophets' name for the Pah-wraiths. Another possibility might be that it is a group of Pah-wraiths.
According to Rene Echevarria in the Star Trek: Deep Space Nine Companion, the Kosst Amojan is referred to as a group or object with the adjective "the", as in "the Kosst Amojan".