Hasin Arnit was a native of the planet Bajor who was part of the Bajoran Resistance and the Maquis.
Bajoran Resistance[]
In 2351, Hasin was involved in the raid on the Tamulna mining facility. He was charged with liberating Bajoran slaves while his lover Limis Vircona sabotaged a cargo ship bound for Terok Nor. Both efforts were successful, but that success came at a price, as one of their colleagues was brutally beaten. He died the next day. Their son was named Yanith after him.
Hasin and Limis married and divorced some time afterwards. Limis then left Bajor with their son in search of a better life. (Star Trek: Lambda Paz: " Revenge a Dish Best Served Cold", " The Tides of War, Part 1").
Maquis[]
Although divorced, Limis and Hasin still enjoyed a cordial relationship while colleagues in the Maquis. Both felt a measure of resentment towards the Federation when their home colony was ceded to the Cardassian Union as part of the Federation-Caradassian Treaty of 2370. Hasin took that resentment to extremes when he believed the Federation shouldered some of the blame for the Dominion's eradication of the Maquis in 2373. (Star Trek: Lambda Paz: " Revenge a Dish Best Served Cold")
Dominion War[]
As one of the survivors of those Dominion massacres, Hasin bribed his way on the ships from various non-aligned worlds to observe Dominion activity. In early-2374, he sent a message to the Federation claiming a Jem'Hadar breeding facility was being built somewhere in Sector 21607. He later to his former spouse, now commanding the USS Lambda Paz, this facility was on a planet in the Tong Beak Nebula. He was later revealed to be a spy for the Dominion shortly before the Siege of Sector 21607, stating that he wanted the Federation to experience the kind of massacre the Maquis did. He escaped the ship. As the battle became a losing effort, he sacrificed his life by laying in a collision course for the Dominion flagship allowing his ex-wife to survive what was a major loss for the Federation Alliance.
Following the battle, Rebecca Sullivan hypothesized that Hasin slipped up because, on a subconscious level, he wanted to get caught and he gave his life as an act of contrition in addition to assuring the survival of the woman he loved. Rebecca understood that Hasin's death still had an emotional effect on Limis after Sullivan lost her husband under similar circumstances a few months earlier. (Star Trek: Lambda Paz: " Revenge a Dish Best Served Cold")