He hid Marth and his surviving Altean knights in Talys after his flight from Altea. King Talys gave Marth comforting words in the hard times, urging the prince to take refugee and play his part in the War of Shadows only when he was strong enough.
When an army of Galder Pirates led by Gazzak attacked the castle, King Talys was rescued by Marth and his knights. King Talys donated some of his greatest soldiers led by Captain Ogma and wished Marth luck on his journey.
Initially, he was not mentioned by name in any of the games, with his name coming only from supplementary materials.