A long time ago, Vikings stumbled upon dragon lands. They were searching for a place to live so instead of needless blood, the two came to a compromise. The Vikings may live on their land with them, as long as they promise to never hurt one of them. They agreed and so they lived in peace.

As a show of their contract, since neither of them preferred the contract to be on paper, the heir of each clan would be married to join the two clans. But the tragedy struck.

The queen of the Vikings was murdered by a dragon who did not agree to live with such humans when it was their land first. War broke out and the contract was soon dismissed.

Years past and soon the meaning behind the war was forgotten. It wasn't until three generations later that the war finally ended by a Viking named Hiccup and her dragon, Toothless.