Jack the Bodiless

From back cover of Del Rey paperback:

In the year 2051, Earth stood on the bring of acceptance as a full member of the Galactic Milieu, a confederation of worlds spread across the galaxy. Leading humanity was the powerful Remillard family, but somebody -- or some thing -- known only as "Fury" wanted them out of the way. Only Rogi Remillard, the chosen tool of the most powerful alien being in the Milieu, and his nephew Marc, the greatest metapsychic yet born on Earth, knew about Fury. But even they were powerless to stop it when it began to kill off Remillards and other metapsychic operants -- and all the suspects were Remillards themselves. Meanwhile, a Remillard son was born, a boy who could represent the future of all humanity. His incredible mind was more powerful even than his brother Marc's -- but he was destined to be destroyed by his own DNA... unless Fury got to him first!