King of Ashes. The Longsword Chronicles, #1

Book One of the Longsword Chronicles. The war with Morloch begins... Gawain, second son of Davyd, King of Raheen, turns 18, and is promptly banished from his homeland for a period of one year and one day. Stunned, he departs the land of his birth, high atop an impregnable plateau, and ventures into the strange world of the lowlands. During his banishment, a ritual which must be undergone by all royal crowns of Raheen, he travels the lowlands incognito, and soon his martial skills are called upon in defence of himself and others.
More, he is staggered to learn that the lowlands are all but paralysed by fear and terror at the hands of Ramoths, a strange and vile cult that seems to afflict the kingdoms with utter impunity. Gawain meets all the kindred races of man. A chance encounter at the edge of the forest of Elvendere introduces him to Elayeen, a haunting elfin beauty destined to become a vital part of Gawain's future. He meets dwarves too, becoming fast friends with Rak of Tarn, a quiet diplomat from the Black Hills of Threlland.
Yet, everywhere he travels, the Ramoth curse has been before him.At the end of his period of banishment, Gawain rides for home, Raheen, intent upon alerting his father to the danger posed by the Ramoth. But it is too late. When Gawain crests the sole route to the top of the plateau, he finds Raheen gone, blasted to ashes... In the ruins of Raheen's castle keep, in the great hall, Gawain finds the Sword of Justice, the only object to have survived the terrifying devastation of his land.
He draws the ancient blade, and swearing vengeance and justice in the name of Raheen, and hard of heart, returns to the lowlands...