Born Letz Cofan, he is one of three orphans brought on board the White Base during the One Year War. While aboard the ship, Letz, Katz, and Kikka became a combination of mascots and troublemakers for the ship, and were involved in several incidents, including Ramba Ral’s last ditch attack on the ship, as well as Char’s infiltration of Jaburo, when they helped to dispose of the bombs. The latter incident lead to their being allowed to stay on the ship, even when she left Earth to return to space for the final offensives at Solomon and A-boa-ku. After the battle of A-boa-ku, the three kids showed their Newtype abilities, when they reached out to allow Amuro to find the lifeboat on which the White Base crew had escaped the ship.
Following the One Year War, Letz was adopted by Hayato Kobayashi and his wife Frau Bow, along with Katz and Kikka. The three visited Amuro Ray’s home in Cheyenne, Wyoming before continuing on to Japan. He stays close to his adopted mother, helping her with the unborn child Frau is carrying.