They're for melting metal for search and rescue, this is totally true, and not a really bad justification.

Well, both of these can also be true. I'm no expert, after all. I just go with whatever makes the most sense with the available information.

I forget whether it was mentioned in the show itself or just something someone wrote on the wiki*, but IIRC the Breaking Mammoth mecha was specifically mentioned to be originally developed for large-scale rescue operations.

On the other hand, weren't some of Aruto's original set of Progrise keys created when Izu told Zea the abilities of the Magia they were up against, and asked it to develop a countermeasure? Which does in a way make them designed for rescue, or at least defense, but in a directly combative way.

*(and I hear that can be very unreliable, though I've yet to spot anything glaringly wrong... but I also haven't been looking closely...)

I'm pretty sure Izu was the one who said it was for rescues. Hiden as a company is all about helping people, so why else would they have a giant satellite space robot?

And I've yet to see anyone present any evidence of the wiki having horrible inaccuracies. Pointless trivia and unmarked spoilers, maybe, but as far as I can tell, most of the stuff on there is taken from some official source.

Fire doesn't always equal combat, so maybe it could be used for land modification. It's not really a theory as it is a fun fact that Toei out on their website on Rising Hopper's description.



On that note, following the topic on Yaiba's upgrade form and using my self-invented "Toei eyes", Yaiba would use Fighting Jackal on her shotriser and just become Valkyrie: Fighting Jackal. It would largely just be Fighting Jackal, but the visor hiding the Valkyrie mask is removed, since the concept art says the Valkyrie mask is actually underneath. And then the white parts of the suit cleaned up to match the AIMs rider suit and the gold much more vibrant.

And then a v-cinema like form would be a Sniping Cheetah. A rampage gatling-like upgrade that makes use of the raider keys like Panda, Buffalo, Penguin, Lion, and maybe throw in Caucasus and Kangaroo for good measure.

Edit: It's Sniping Cheetah as to mirror how most of Vulcan's forms are brutish and heavy in design, yet Rampage in stark contrast is a lighter and more agile form.

I really curious to Joker Card ability.
What if Kamen Rider Blade are obtained a Kamen Rider Blade Joker Form as extra final form if Joker Card are used in Blay Buckle?

Also, here are the potential uses for the Progrisekeys made by Hiden.
Rising Hopper: Unsure
Flying Falcon: The ability to fly is incredibly helpful
Sting Scorpion: Antidotes
Flaming Tiger: Not only is it a flamethrower, it's a blowtorch. Blowtorches can be used to get things out of the way
Biting Shark: Jaws of Life
Breaking Mammoth: It was designed to be used for Large Scale Rescue Operations.

Meanwhile, one What if form I have for Zero-One is "What if Zero-One used the Zetsumerisekeys to get new forms? How would they look like?" For the Mammoth Zetsumerisekey, I think it needs to be a more "Mighty Action X"-like form than the Breaking Mammoth Progrisekey's "Suika Arms". Or maybe it could be the "PROTO-10 Watermelon Arms" to the Breaking Mammoth's "Suika Arms".

Another group of potential forms is Kamen Rider Zi-O Showa Rider Forms and Zi-O Amazons Forms. From 1 to Black RX. They have shown most of the Showa Rider Ridewatches, in all, they have shown 1, 2, V3, Riderman, X, Amazon, Stronger, Black RX, Shin, ZO, and J. For Amazons, Amazon Omega, Alpha, and Neo have appeared. And in the Ziku Driver, we can hack in Black, ZX, Super-1, and Skyrider. So, therefore, they have so much room. And also, more Secondary Rider Forms for Geiz would be cool. In the Geiz Majesty Ridewatch, it references G3, Knight, Kaixa, Garren, Ibuki, Gattack, Zeronos, Ixa, Diend, Accel, Birth, Meteor, Beast, Baron, Mach, Specter, Brave, and Cross-Z (I copy-pasted that). And there are Ridewatches for most of these. All they need is to release DX Versions of those Ridewatches which don't have DX Versions, so far. Seriously, it would be crazy simple.
Meanwhile, when it comes to non-Zi-O Forms, I say some What if Forms that I would find cool is Ex-Aid with the newer Legend Riders. From Zi-O to Saber. And what about Gaia Memories based upon the Legend Riders after Double? Basically, what I am saying is for all the time when there are Collectable Devices where all of the sounds are in the Device, like Gaia Memories, Rider Gashats, and Lockseeds. When new Lockseeds came out, I was surprised. So it wouldn't be a surprise to see new Rider Gashats or new Gaia Memories. Seriously, the final Legend Rider Gaia Memory was Kamen Rider Wizard.