heir

manttelinperijä, vallanperijä

perillinen, kruununperillinen Someone who inherits, or is designated to inherit, the property of another.
(w) (1564-1616)

I am my father's heir and only son.

And I his heir in misery alone.

"I wish we were back in Tenth Street. But so many children came(..)and the Tenth Street house wasn't half big enough; and a dreadful speculative builder built this house and persuaded Austin to buy it. Oh, dear, and here we are among the rich and great; and the steel kings and copper kings and oil kings and their heirs and dauphins.(nb..)"