Prior to Ultima IX, his people had been infected with pride, erecting a huge Underwater City. Vasagralem hadn't been in favor of this. As a result he and his secretary and bodyguard Desbet had to go into exile when his people removed him from power.
The Avatar first met him in Castle Britannia, where he'd held cousel with Lord British. Vasagralem told the Avatar of the fate that had befallen his people, and that right now they also had lost the purple codex lens, something that he'd sent Desbet to deal with.
After the destruction of the city, he blamed the Avatar for it and decided to take vengeance for the supposed end of his people by bringing Raven before the court of injustice in Yew, where she was sentenced to lifelong imprisonment. However, after being presented by the Avatar with a queen-egg to restart his people, Vasagralem knew that he'd done wrong. So he helped the Avatar to sneak into dungeon Wrong to free Raven and later told the truth to the reformed court of justice, to clear Raven's name.