Leftrin is the captain of the Liveship Tarman, which has been in his family for generations, and uncle to Skelly, his deckhand. He has occasional impulses, which he follows. These have never led him wrong, and whenever he has not followed them he has come to regret it. In The Rain Wild Chronicles he discovers a lost cocoon, or serpent case, in which the sea serpent morphs into a dragon, on the shores of the Rain Wild River which he uses illegally to make custom upgrades to the hull of his liveship. Additionally, he makes stumplike legs and a short tail for Tarman to wade with or to push himself forward in the water.
The illegal modifications to his ship leave him open to blackmail and he is forced to occasionally acquiesce to Chalacean interests, making him try to obtain dragon parts for the ailing Duke of Chalced . A blackmailing Chalcedean trader leaves Jess Torkef, a hunter, in his midst. This propels him to being involved in the eponymous Tarman Expedition in which his ship, passangers and Dragon Keepers aid the march of dragons to the lost city of Kelsingra. Jess wanted Leftrin to kill an ailing silver dragon while it was gorging on a carcass, but while Jess's back was turned, Leftrin tried to kill Jess, but was unsuccessful because of a horrible earthquake which caused a minor tsunami and the acid level in the Rain Wilds River to rise.
Leftrin began a relationship with Dragon scholar Alise Kincarron Finbok, and eventually stays with the keepers and dragons in the Elderling ruins, or Kelsingra