Kamen Rider Saber Spin-Off Kenshi Retsuden Episode 1: "an episode of Kamen RIder Slash & Buster" will be the first in the entry of this Spin-off.
So this episode will focus on the reason why Daishinji lost his ability to transform into Kamen Rider Slash in the first place. This will also focus on Ryo Ogami who is protecting the young Swordsman as the Shield of Sword of Logos.
So this sneak peek starts with Tassel narrating about the show and then the actual episode starts. The story takes place between Episode 8 and Episode 9 and hence called Chapter 8.5. Daishinji is seen scanning King of Arthur Wonder Ridebook and Ryo-san comes over there. He sees the Onjuu-Ken Suzune and then Daishinji talks about to prevent any like the incident that happened 15 years back.