All unknown defendants, including the heirs and devisees designated in the complaint, shall have the same rights as are provided by law for other defendants upon whom summons is served, and the action shall proceed against them in the same manner. Regardless of any legal disability, any unknown defendant, including any heir or devisee designated in the complaint, who has been served, and anyone claiming under him, shall be concluded by a judgment in the action as if the action were brought against and personal service made upon that person by his or her name.