In Saber + Zenkaiger: Superhero Senki, Kamen Rider Saber members will get sucked into Swordsmen's World - Hakkenden. Over there Touma and others are dressed up in Samurai outfits.
Along with meeting up with Doggie Krugger / Deka Master, Shou Ronpou / Ryu Commander & Raptor 283 / Washi Pink, they also meet up with three Legend Heroes - Aruto Hiden / Kamen Rider Zero-One, Shiguru Oshikiri / Kiramai Blue & Chiaki Tani / Shinken Green.
Fumiya Takahashi's voice was previously heard in the Main Trailer. But it was not confirmed by Toei in the announced cast list previously.
Shogo Suzuki will reprise his role as Chiaki Tani / Shinken Green from Samurai Sentai Shinkenger. It's been 12 years since the broadcast of the show. It would have been a fun if somehow they could have incorporated Keisuke Soma (Master Logos / Kamen Rider Solomon) as Shinken Gold too.
Atom Mizuishi will also reprise his role as Shiguru Oshikiri / Kiramai Blue from Mashin Sentai Kiramager.
Just like how Saber members are sucked up in Hakkenden World, Zenkaiger members are sucked up in Journey to the West World. The World on which the Ride Book Saiyuu Journey is based. In this world, they meet the four Taros Imagins and also the Demon King - Kamen Rider Zi-O.
So Okuno will reprise his role as Sougo Tokiwa / Kamen Rider Zi-O. Sougo Tokiwa appears out of nowhere in between Zenkaiger & Imagins' battle against the enemies. Zenkaizer tells him "It's dangerous for you to come to this place" for which Sougo replies, "It seems I am a Demon King".
Considering the reset of the timeline, Sougo Tokiwa's story is complicated now. The way he said "It seems I am a Demon King" seems like there is some involvement of Oma Zi-O for his appearance.
To Know more on Deka Master, Ryu Commander, Washi Pink & Taros Imagin Reprisals: