The story of Wilhelm and his first encounter with Theresia is told in the light novel 's spin - off .
He holds a strong grudge against the White Whale for killing his wife , Theresia van Astrea .
The story of Wilhelm and his first encounter with Theresia van Astrea is told in the light novel 's spin - off .
He holds a strong grudge against the White Whale for killing his wife , Theresia van Astrea .