Mystery boy (a owl house story)

Blights, one of the most esteemed and richest family's of witches in the boiling isles. They have three kids. Emira blight, Edric Blight, and the youngest amity blight. but the parents of these children have a dark secret, there once was a fourth child. The oldest named oden blight. He was a prodigy for magic and he did everything right, but there was one thing that made his parents supposedly kill the boy. He didn't do everything his parents command him to do. And after so many days of this happening he was in a fatal 'accident' when a spell was miss fired onto the boy sending him off the edge of a cliff into a boiling hot sea. Years later after this has happened there has been incidents where some of the blights business partners have been brutally murdered by the same thing. Blue flames. What coincidence is this and why is this happening to the blights. Find out in THE MYSTERY BOY