Is this a good book trilogy idea?

27000 years ago with the earth had another continent called Alania which was once governed by a group of god like being until one day when they all disappeared and the fueling if Alania was up for grabs a war broke out between the elumon the olemun and the neguman (different division of men who all have a distaste for each other) they all wanted to become the leaders of the land this war spanned over 86 years. Until one day the king of the Neguman asked the gods for a gift, a weapon which would allow them to win the war they obliged and crafted a weapon "The Dark Diaomd" and gave it to Hume this weapon made him immortal gave him the powers of the Wisimag(wizards) and basically made him the most powerful man I'm Alania and they won the war but the king of the Elumon demanded for a weapon as well but they did not give it to him so he went to the Wisimag and demanded they make something and they did they made him a sword who could shatter the diamond the only thing that could so he used it but instead of destroying the diamond he kept it for him self and was now the king of Alania.

537 years late

The neguman have been reduced to a band of rebels ( also known as The Falkens) trying to fight the elumon king or emperor now which was mostly a lost cause untill A 16 year old boy named William Caster finds a dark diamond in

the albrae forest which Led the rebellion and all who align themselves with them believe he is the true king and the only person alive who can fight and kill the elumon emperor

It would be a trilogy

Caster: The Dark Diamond

Caster: The Wrath of the Diamond

Caster: The Creed of the Diamond