He asked for Xena's help in "Warrior... Princess" when his daughter, Princess Diana, was targeted by assassins. This led to Xena and Diana switching places for the day. He was on death's door in "Warrior... Princess... Tramp", when his daughter and grandaughter are targeted again. This led to Meg impersonating Xena, Gabrielle being thrown in the dungeon, Joxer getting the wrong idea, as well as Joxer getting slapped by a princess, man handled and thrown in the dungeon too.
King Lias is portrayed as a very fair and kind ruler. He is also presented as being well loved and admired by his people. It is unknown what happened to his wife (whom is presumably also Diana's mother) but she is assumed dead. At the end of "Warrior... Princess... Tramp", King Lias has hired Meg as his personal chef, so it is assumed that he enjoys spicy food, as that is apparently Meg's specialty.
King Lias, his daughter, granddaughter and son-in-law are never seen again in the series, but, after Xena and Gabrielle's 25 year sleep, King Lias's personal chef, Meg, has moved on and works with her husband. It is implied that she has been working there for majority of the 25 years, thus, it can be assumed that King Lias died shortly after the events of Warrior... Princess... Tramp.