Was the Ivory Champion's only job to be the Second City governor's personal yojimbo? Because in my campaigns post-Emperor Seiken I've expanded the role of the Ivory Champion to encompass any gaijin who has shown unquestioned fealty to the Emperor and Rokugani society; after Shinjo Tselu, I've given the championship to Arjuna Singh.
I've also done something similar to the Pearl Champion: it would be given to any non-Shadowlands non-human who presents devotion to the Emperor.