In late 2374, he represented the Romulan Star Empire at a meeting of the Federation Alliance on Deep Space 9. The purpose of the meeting was to discuss Romulan involvement in the proposed invasion of Cardassian space, specifically, the Chin'toka system, which had been found to be a weak spot.
Like most of his people, Letant had a disdain for Klingons, something which aggravated General Martok, who was representing the Klingon Empire at the meeting. After expressing reluctance to join the invasion, Martok and Letant traded insults, with Martok calling Letant a coward, and Letant calling the general a "Klingon jackal". This continued until Letant loudly told an aide: "Notice the primitive rage in his eye... the uncontrolled brutality. Klingons can be quite entertaining, don't you agree? I think every Romulan zoo should have a pair." This caused Martok to reach for his d'k tahg, but he was stopped by Benjamin Sisko and Worf.
Letant was finally convinced by Sisko, Worf, and Admiral William Ross that the only way to defeat the Dominion was to destroy their shipyards and weapons plants and to force them to retreat to Cardassia Prime. Sisko also told Letant that that was "a goal we all share. Klingons, Humans, and Romulans."
A Prophet later took Letant's form in a vision that Sisko experienced, in which they told him not to go to Cardassia.
Several hours later, the real Letant was present at a meeting with Sisko, Ross, and Martok. Even after the discovery of the Cardassian's orbital weapon platforms, Letant continued to support the attack, saying that Romulans "live up to our agreements." After Ross wished them all good luck, Letant told him "Romulans don't believe in luck." (DS9: "Tears of the Prophets")