He already is, and Cayde's bet was whatever kills him to become Hunter Vanguard, which was Uldren, Uldren dies by us and comes back as a Guardian and took a path of redemption even having to relearn what he did to Cayde. Uldren won, Cayde died, then he came back due to Crow's final accidental wish to Riven, allowing Crow to apologize for his actions and Cayde basically handing him the mantle (also cloak). Whether we wanted it or not...we stepped into a war with th...wait no, Crow is Vanguard now, Shiro-4 never would want that title anyway.