Thread:Whovianfan/@comment-5616350-20160804020106/@comment-6945486-20160810001445

I'd say probably a cameo but subtle with Zouken Matou by only his servant True Assassin reporting to a character's name with ??? that is really Zouken.

http://legendsofthemultiuniverse.wikia.com/wiki/True_Assassin_(Fate/stay_night)