Khathelet is one of the ruling houses of the country of Lycia, in Fire Emblem: The Blazing Blade. Lycia being one of the major countries of Elibe, the continent where the game takes place.
Khathelet is one of the less important houses of Lycia, in terms of the events in the games it is involved in. House Khathelet's ruling territory is relatively small when compared to Ostia, Pherae, or even Laus.
Geographically, Khathelet is located north of the Lycian territories of Caelin and Tania. Also to the north of Khathelet is the territories of Araphen and Tuscana, which themselves border of the country of Sacae. Finally, to the east of Khathelet is the military superpower that is the country of Bern. Meaning that, Khathelet was one of the first Lycian territories to be invaded during Bern's attack on the Lycian League. Khathelet is clustered in among the smaller Lycian territories that exist on the countries east most edge.
Fire Emblem: The Blazing Blade
In Fire Emblem: The Blazing Blade, Lyn passed through Khathelet on her way to Caelin. While in Khathelet, Nils made an appeal to her group for help as he was being pursued by a group of Black Fang members. Later, Lyn agreed to help Nils and fought the Black Fang on Khathelet soil, eventually defeating them. Chapter 7 and Chapter 7x both occur in Khathelet.
Khathelet is mentioned in the game by Eliwood, being one of the Lycian territories he convinced to stay out of the Caelin inheritance dispute, along with Laus, Tuscana, Tania and Santaruz.