Hostorren was born in the city of Oros, and lived as a promising sellsword until he found enough wealth to train as a blacksmith. He found that he was much better at building weapons and armor than killing, and soon decided to travel to Westeros. During his first years in the Seven Kingdoms he did important work for many lords in the Stormlands, Crownlands and the Reach. After helping the King of the Reach with a number of rebellions that spanned three years, he amassed enough wealth to buy lands west of the Stormlands, and founding House Harrigon. The castle he build would soon be called Hornworth after his death.
While the head of a small vassal house under their liege lords of House Mertyns at the time, Hostorren planned on his descendants controlling a powerful house that all of Westerros would recognize. For years he began the construction of an enormous forge underneath his castle. By the time he was 40 years of age, he had completed a sizable forge fit for a city, but needed workers. He asked Lord Safford Mertyns for men, and also asked to send a raven to King's Landing to send him the condemned criminals to be sent to Hornworth instead of the Night's Watch. Lord Mertyns refused, and Hostorren returned to Hornworth. Hostorren married Linetta Swygert, but left to carry on his work in the forges after consummating the wedding. It would be a few years until Linetta gave birth to Corloss, Hostorren's heir.
Instead of finding workers from across the realm, which would have taken years, he sired them instead. Hostorren fathered many bastard children, and trained them all as blacksmiths, both his sons and daughters. Two of his sons, Ronnis and Jojan, both strove for higher ambitions at an early age, and both squired for Lord Mertyns son and heir Josuan, gaining knighthoods.
Hostorren died at the age of 87, never completing the forges underneath Hornworth. He was succeeded by his only true-born son Corloss. His great-great-grandson Durran completed building the forges of Hornworth. There are small statues of Hostorren littered throughout the forges.