Samanosuke and Guildenstern
Neither Samanosuke Akechi nor Guildenstern make an appearance in this game (though Guildenstern is mentioned in one of the files that Jubei finds, as well as in a drawing during the opening narration). Samanosuke also appears in the aforementioned opening narration in which he is fighting Fortinbras.
Read more about this topic: Onimusha: Samurai's Destiny