Hadlo was a Cardassian male and leading member of the Oralian Way.
In 2318, Hadlo was sent, along with his chief advisor Bennek, to Bajor as part of a reconnaissance mission that was cloaked as a mission to return the dead crew of the starship Eleda. While on Bajor, Hadlo established good ties with Kai Meressa and she allowed him to view the Orb of Truth. His vision led him to ask Meressa if the Way could be allowed to establish enclaves on Bajor, in order to save the faith and trade religious knowledge, a request to which she assented. Soon after, Hadlo was imprisoned aboard the Kornaire and offered the enclaves as a way for the Union to establish a foothold on Bajor. This got him released from the brig and he returned to Cardassia where he organized an exodus of Oralians to Bajor.
By 2323, Hadlo had sent many followers of the Way to Bajor and had also become increasingly paranoid. His paranoid beliefs soon came true as the military began rounding up followers of the Way, so Hadlo led many followers into the Badlands aboard poorly equipped freighters. These freighters were soon hunted down by Dal Skrain Dukat of the Kashai and destroyed, killing Hadlo. (TLE - Terok Nor novel: Day of the Vipers)