Talyn is Moya's child, a young Leviathan engineered by the Peacekeepers to possess the characteristics of a gunship, including a large cannon. Despite this, he's loved deeply by his mother. He is named after Aeryn Sun's dad, Talyn Lyczac.
Unlike other Leviathans, Talyn was born with integrated weaponry and does not require a Pilot (though he is capable of having one[1]), instead responding directly to voice commands.
Talyn is commandeered by Bialar Crais at the end of Farscape’s first season. Crais accepts Talyn's "Hand of Friendship" (the direct neural interface between a Leviathan and its captain) and becomes somewhat of a father figure to him. However, when the PKs learn of Talyn's existence, a retrieval squad led by Xhalax Sun is sent after them.
During the third season, several members of Moya's crew, namely Aeryn, Stark, Rygel, and (one of) the John Crichtons, join Crais aboard Talyn. Talyn becomes increasingly emotionally unstable due to his Peacekeeper qualities, even destroying a hospital ship and firing at Moya.[2]
He and Crais ultimately sacrifice themselves to destroy Scorpius' Command Carrier, keeping Crichton's wormhole knowledge out of Peacekeeper hands and allowing the Moya crew to escape. His remains are taken by Moya to the sacred Leviathan burial space in "Dog with Two Bones."