Kento's red eyes makes me assume they're going to do a "brainwashing" subplot and Kento would briefly use Kurayami and eventually go back to Ikazuchi or use it alongside Kurayami.

In a perfect world, I'd like Kento be revived somehow and assume the ""protagonist"" role and Touma to switch to Deuteragonist role while he's still in Primitive Dragon. Have Kento take up both Ikazuchi and Kurayami (or the former for now) and get some sort of "Super Alangina" form or a Calibur/Espada fusion form and save Touma from Primitive Dragon. In a effort to prevent Touma from anymore suffering.

All the more reason to paint him in Los Angeles Lakers colors and sell the toys at a higher price. :lolol

Though, imagine if Saber were to insert the Jaaku Dragon Wonder Ride Book into Primitive Dragon. That would be scary.

Though, I have just realized that if Touma were to insert Lion Senki into Primitive Dragon, he would literally be a Lionheart. Lionheart is a reference to King Richard the Lionheart from the Robin Hood story.

And also, what would happen if Saber or any other Rider from Kamen Rider Saber were to insert the Book Gate Wonder Ride Book into their Transformation Device? It hasn't been shown to have a Transformation Page, yet. But, what would happen?

Jaaku Dragon doesn't seem to be that special of a WRB, unlike King Of Arthur. It'll most likely just take form like any other Primitive form change.

I Imagine a hole appearing on the rider if they put the book gate on their belt, sucking them in.

What if Kenzan's future upgrade be something like Ryugen Yomi, but with a book based off of Fuma Kotaro?

I guess. Though I think that it would allow him to wield both Kaenken Rekka and Ankokuken Kurayami like Lamp do Alangina allowed him to wield both Kaenken Rekka and Raimeiken Ikazuchi. Now THAT would be scary.
But what if King of Arthur was inserted into Primitive Dragon? He would be able to wield Kaenken Rekka, Kingexcalibur, and have the power of Primitive Dragon. That would be extremely scary.

Also, considering the warped portal found on the Story Page Sticker and the Cover Page of Primitive Dragon, inserting the Book Gate Wonder Ride Book could be interesting. Either that or Eternal Phoenix.

The next thing is this. How about some speculation about what if all the Riders in Kamen Rider Saber got final forms or at least upgrade forms?

And finally, what if they were to release a group of Wonder Ride Books/Alter Ride Books based upon Famous Cryptids from around the world? Like the Jersey Devil, the Moth Man, the Owl Man, the Loch Ness Monster, the Chupacabra, Bigfoot/Sasquatch, etc. They have done the Yeti in the form of Shirayuki Yeti. So what about more Cryptids?

Probably not. Scans show Primitive Dragon with Lion Senki and he’s still just using Rekka.

On the note of Cryptids, they would likely be covered by the Legendary Animals WRB genre, seeing as there are only three.

I have just realized that the way Primitive Dragon works, it allows for Alter Ride Books to be inserted. Imagine forms of Primitive Dragon with the powers of the Alter Ride Books.

Desast could legit get taken out of the picture by being stolen.

Just a hunch, but I get the sense that would be just as bad for Touma as it would be for Desast... I could see it being a significantly more dangerous version of previous "two characters sharing a body" forms