AN: *Sees Guest review about Cross-Z/Shiraori fusion.* Mmm. A fusion between a devourer of worlds with power over dragonfire and blackholes and a spider goddess, master of dark arts as well as a prodigy in space magic, not to talk about their imagination, mastery over their abilities and all the media consumed between the two plus Pandora Box *cue Metal version of One Winged Angel, with nearly everyone terrified, a few cheering and the rest facepalming for the godlike, eldritch, otaku, hermaphrodite, dimension hopping, half-alien, half-spider,half-human, world destroying, pose obsessed, slacking, gourmand, possibly autistic, genre savvy and somewhat benevolent but misunderstood force of ultimate destruction, all while D and Evolt make bets in a private projection room with massage chairs that include cup holders, all while eating Toriko-verse food and drinks, wearing 3D sunglasses.* In your own opinion, what would you do with all those crazy powers, especially the dimension hopping one combined with otaku needs and knowledge?

Maybe some badass quote like "Now I am become Death, the Destroyer of worlds." (Bhagavad Gita) or something. Or just laze around, all the while picking all kinds of useful or shiny tech and magic like a giant robot just because you want and can.

… Ok, maybe developing a literal God-complex would be a bad idea.

And the other Guest with story suggestions, I had some of those ideas planned though some others made me think about implementing, thanks.

As for the one who said that using Pandora Box' power would end up badly, remember that as long as you had the smarts and/or the right genetics (Sento Kiryu and Ryuga Banjo) you could use the Box in multiple ways like the Genius Fullbottle and the White Panel. Though I admit that only Evolt was the one to use the full power of the Box but was ultimately defeated by it thanks to another application of the same item. The problem with Namba was that he was so stupidly greedy that he never thought of the Number One anti-Evolt contingency: do NOT let Evolt be a part of your evil plan or any type of plan. Machiavelli would have facepalmed at the guy. And while Evolt and other Riders have the potential to defeat gods or have done so, D is so OP that you would need full Decade or Zi-O levels to do anything to her in a reasonable timetable though Ex-Aid (with Hyper Muteki and Mighty Novel X) and Gaim (as the Man of the Beginnings) may be able to match her. She didn't demonstrate her full power at the moment so we have no idea how BS are her haxes or destructive potential though we can guess with her being a powerful Death Goddess that was able to create a Reality-Warping RPG-like System to a whole planet without a sweat that would make Kuroto Dan's mouth foam from fury before he arrogantly proclaims his Bugster Virus as superior, tempting fate as the memetic, God-complex, game developer, Reality-Warping, 99 lives cockroach challenges a bonafide multiversal goddess of the Underworld who's also a hardcore gamer and doesn't take anything seriously unless it's to escape work and not bore herself.

… Okay, let's recap.

First, I was teleported to another world. With my chair, for some unexplained reason.

I found Kamen Rider merchandise that turns out to be real after all and can only use part of it without shocking myself or transforming into a monster or dying.

Then I discovered that my body deaged as well as became a redhead. Uh, now that I think about it, it reminds me of Ryuga Banjo, the Rider of whom I have his things.

And some time after, I contacted another stranded person: Japanese girl with the name of Hiiro Wakaba, or Wakaba Hiiro if you follow Japanese customs, who turned out to be a goddamn giant spider!

… Is my life some cliche manga or bad fanfiction? I mean, the only manga example that I could think of is a Red Ranger being isekai'd and that's all. And there aren't many good fanfics of Kamen Rider Inserts in high fantasy medieval worlds. Oh, wait, there's that one with Zero-One and Fire Emblem: Three Houses. With both only just beginning… so I can't use those as guides for my situation.

Anyways, I'm now fully aware that this situation, despite how weird it is, is real. If my painful clash with my own chair while trying to escape a monster spider didn't prove it, then I don't know what.

Speaking of the spider.

Hiiro Wakaba.

Using my knowledge of multiple Isekai tropes and arming myself with patience, knowing that I have to deal with a giant, awkwardly social and teenager spider girl, I found out that all her class died due to a Hero and Demon Lord launching an attack to an Administrator, one of the Gods that are in charge of this world. Then, that same Administrator reincarnated the classmates and teacher into this world, giving them unique skills and sometimes being born not as a human.

Well, at least the theories that a God and RPG mechanics were involved were true in this case. Heck, I even imagined myself grinding up like crazy to become OP like any true gamer, though Wakaba told me that I had no connection to the System or that there was a bug on it, which deflated my hopes.

Is it because of my Rider System? The ones appearing in the Build series were some of the potentially most powerful ones of the entire franchise, so maybe being unable to access the System was a payoff to make things balanced.

Though you may ask: if that was an attack against a God, why was an entire Japanese classroom blown up?

Easy.

D, God in question was one of the students there. Yeah, I wouldn't believe it. Though that would also make sense. There were plenty of myths of deities disguising themselves as mortals in order to partake in the joys of the lower world, like fucking nearly everyone.

Screw you, Zeus. And many other Megaten entities, by the way.

Though I wonder, was D what transported me too or was it another one who did?

That was only the beginning, and both Wakaba and I were becoming tired. Our conversation wasn't the most efficient in a time-content ratio.

So I indulged her wish to use my phone, I would also understand the need of advanced technology after being separated from it for who knows how long.

And that was when the next bombshell happened.

"2021?"

"Uh, yeah, that's the year we're now in."

"Last date I remember from Earth was 2015."

… Yeah, apparently there's now a 6-year difference between us, in a time travel sense. Which is not helped due to Wakaba not knowing for how long she has been here.

We began launching idea after idea: from both of us being from an alternate Earth each; being transported long time after their deaths; time dilation being inconsistent between worlds or just the classic time traveling mixed with dimensional jumping. Though we haven't reached a conclusion yet.

At the end, I ended up trying to relax in my chair while Wakaba was busy playing with my phone if the music was something to go by.

So we're both trapped, by both space and time. There's no guarantee that if we returned, it would be in a stranger's Earth, a future one or both. Though I think mine and Wakaba's Earths are different. I mean, I think an incident where a lot of people died suddenly from an explosion in a school, no matter the country, would have made it into the news, which I don't think I heard of.

I sighed. This is becoming complicated.

Then, I was hit with an idea.

"Hey." I don't know if she's listening though I still continued "How about making an alliance"

That was when she stopped the music and turned back to me. I know spiders can't change expressions though I think I felt confusion from her gaze alone. Those eight eyes are morbidly… interesting.

"What?"

"I mean, what if something were to happen? Like an army or a world destroying being or an army of world destroying beings came here to destroy us all?" Then I blinked "How are the power levels here?"

"High."

Knew it. If there are gods and interdimensional attacks, of course there would be bound to be some high tier stuff here.

"Sooo… I have something that may possibly help us though I need time to-" "You're a Kamen Rider."

Whatever I was going to say died in my mouth when I heard her (rudely) say that. I sighed "You watched the belt, right?"

"Yeah."

I was left in silence, pondering what to say next though the most it came from my mouth were mere indecisive noises.

That's it, screw it.

"Okay, I'll admit it. I don't want to be alone. The nearest Earthling around may probably be kilometres away, I don't want to die from anything, whether they're monsters or locals. I have no freaking idea if they'll even have the same languages as us, nor if they're carrying unknown diseases. Wait." I stood up "What if I end up introducing Covid." I sat again deflated "Bah, they have magic. That one may not be a problem. I don't even have Covid, anyway."

I sighed though I felt like I was getting out a lot of emotions with it "Sorry about that. I was never in a situation where I was… that lost. You wouldn't know if there's food somewhere, right?"

I was surprised when she materialized an apple and gave it to me "Uh… I was only asking where there was food but thanks."

Huh, it tastes like the ones from Earth.

"Usually, knowledge of a more advanced world would make an otherworlder very useful but I'm not a scientist or craftsman. Heck, I think I forgot a lot from school and what I remember is because I read it from the internet. But like you said, I have this!"

Cue Build Driver raised to the sky with imaginary Zelda sounds.

"This Driver comes from Kamen Rider Build, the 2018 season of the franchise. Though I may have the secondary Rider's transformation items, Banjo Ryuga or Ryuga Banjo, may be one of the few Riders to surpass the lead ones in full power." I grinned "His final form is able to create black holes, the same power the villain used to devour planets."

I could see Wakaba open her spider mouth with disbelief. Wait, did spiders have teeth? Uh, better not to think about it…

"Unfortunately, Build introduced the Hazard Levels, which explained how Riders were able to gain new forms as well as keep up with weaker ones despite the villains having higher stats. It's like a mix of RPG leveling and emotional powers, I think? The more you fight and discharge your emotions, the stronger you become, simple as that. Or you inject yourself with more Nebula Gas, your typical physics-defying, biology-breaking Rider phlebotinum."

Once I finished the admittedly abridged version of how the Build System works, I waited for more questions.

I once again had to ask her if she had some questions.

"What's Covid?"

I snorted. Of all things to ask, it had to be THAT? That's pretty funny.

And it wasn't until much later that I remembered to ask if she wanted the alliance or not.

SICiaRFW,Iss

Wakaba here (again)! Today, we begin the first of a series of info dumps about the lore of a pure innocent girl transmigrated into a spider by an Evil God and a Kamen Rider Self-Insert that honestly has no idea of what's happening and may or may not come from the future.

Jeez, how tiring is it to tell someone's life to a stranger? Even a small part of it? At least, this Lucas didn't seem to be a dull discount Isekai protagonist but one of those self-aware, genre savvy fanfic SI protagonists that fear for their lives and want to obtain the Golden Ending without them or anyone else dying.

And his explanation of his powers was something I knew beforehand due to his big mouth. With the exception of the world-eating black hole. That was high scale end-series stuff and a pretty powerful one to fight the Administrators with! Hehehe.

And I never expected that the world would suffer a global viral outbreak from China, of all places.

No way.

There's also the possibility of parallel Earths so I'll take it with a pinch of salt.

But the reasons why he wanted the truce? Huh… reminds me a liiiitle bit of when I was weak, alone, outnumbered, weak, lost, confused, weak. Did I say weak? Add other humans that may be aliens to us (or are we the aliens?) and you may probably have the words "You died" in your Game Over screen with no continues. Data deleted. A Nintendo-hard roguelite.

Though lucky for you, my own personal Masked Godslayer of Justice~ I have plans for you, hehehe. Training, food and medical services are included, if you reject this offer then you're an idiot!

We were in the middle of signing (read: say yes) when wild adventurers appeared!

Crap! Dedicating all my mental capacities towards the Kamen Rider (and his phone), distracted me and made me lower my guard.

"Weren't you supposed to be watching over?" Kamen Rider reprimanded his robot dragon in a low voice, which I heard thanks to my Detection skills.

It just roared indignantly as if saying 'Really? Did you expect me to be in charge of everything?!'

Or something like that.

Strangely enough, none of the adventurers are neither moving nor attacking. Just standing there awkwardly. Excuse me, this is a private reunion between a Japanese reincarnated spider and a summoned Spanish Kamen Rider, could you just wait outside for a moment, please?

Now that I think about it… are they here to investigate the recent bandit deaths? Mayyybe I shouldn't have gotten away.

Wait, I think I recognize two of those guys. When I was still in the Labyrinth, my first human contact were a bunch of hurt adventurers. Long story short, in exchange for some fruit, I healed them. Talk about equivalent exchange!

And I see they're now talking with their fellow adventurers. Maybe they're telling them that I'm not a menace? I even was solving their bandit problem. Oh, wait that's why they're checking.

Oh? One of them is approaching us. Though more like she's approaching me. And is that a fruit she's holding out?! For me?!

You didn't have to do that. Though I spent a fruit feeding the Rider, so I'll accept it with mucho gusto! Itadakimasu.

"Uh." I heard the Kamen Rider say "Never knew spiders eat fruit."