Part I: A Malaria in Solaria? The Backstory Lacks Glory!
The first of many, many, many things I'd like to tl;dr on is the lost city of Solaria. What is Solaria? Did it arise from Kabapu's mustache-saturated dreamscape as a sister city to the Mushroom Kingdom? Why haven't they hunted down and killed Sumiyoshi, who is clearly the last Highlander? When is Rikudo going to reveal that Il Palazzo is actually Lord Xenu?
To answer exactly one of those questions, Solaria is an off-brand Atlantis, the only civilization that existed 20,000 years ago. According to Kabapu, it was destroyed due to technological hubris. Hubris and Il Palazzo. As one of the few survivors, he made it his mission to kill the other survivors. I mean destroy the overtechnology so such a tragedy would never occur again. Also kill the other survivors.
Kabapu is a crazy bastard, but all the evidence indicates not lying about Solaria (at least, he's not lying about it being old, technomological, and kersploded). But the spin story he puts on Il Palazzo is completely contradictory with how he acts in private or when he's talking to Momochi. While his hatred for Il Palazzo does blossom in later volumes, Kabapu is originally regretful of losing Il Palazzo's friendship, and is willing to apologize to him. Even later on when Il Palazzo has been totally screwing him over, he's like "WHY D:" and "THIS ISN'T LIKE YOU IL PALAZZO D:" Pretty forgiving for somebody whose nice city with good zoning supposedly got destroyed by this guy, don't you think?
It's harder to say how Il Palazzo feels about Kabapu, because his feelings are strange and mysterious and possibly nonexistent. He calls Kabapu a worrier and a savage, torments him, and revels in his pain, and yet when Il Palazzo is finally succeeding, he just bitches about being bored. The modern world is just a game for these two, and there's no reason to believe the ancient world wasn't the same. That having been said, I don't think it was either one of them who destroyed Solaria. No, I think it was Excel.
It's never really stated what Excel is in canon, and after all, it's kind of the point of the series to figure out. However, it is stated that Ropponmatsu was once the queen of Solaria, and the connection between the two is undeniable. We know that one is the copy of the other, though it's never really clarified which is which, or even how they are connected. Fandom likes the theory that Excel is the body and Ropponmatsu is the soul (because Kabapu claims to have sealed the queen's "essence" in Ropponmatu's core, and because he says that Excel looks like someone he once knew when he meets her). Personally, though, I think that Ropponmatsu is the copy and Excel is the real deal, body and soul. I mean, she is the main character.
The other reason I think Excel is the real Solarian queen is because she has that one dream that one time that looks suspiciously like an emo flashback. Since I've already got the scans uploaded, I'll paste 'em in.
Page 1,
Page 2. Note that Il Palazzo's eyes are different and he's talking an awful lot like they're going to DIE. I really enjoy how it's like... clearly the most depressing flashback ever but Excel's just like, "FUCK YEAH, I'M DREAMIN' 'BOUT LORD IL PALAZZO!! 8D" Also on this note, one of my many pet theories is that the technology that destroyed their society was some kind of bitchin' immortality research, but I have no real evidence for that whatsoever. \o/
Aaaaaanyway, when Solaria was destroyed, it's pretty clear that the queen died. At least, I'd HOPE she died before Kabapu got the idea to put her soul in an Energizer battery. And you can't really tell with Il Palazzo, but when you consider that he doesn't know what vending machines are, it might be safe to assume that he died, too. GOOD THING THEY LEFT THOSE HORCRUXES FRAGMENTS BEHIND, RIGHT?
And that's about it for Solaria! Unless people have questions because it makes no sense. Which it probably doesn't.
Stay tuned for Part II: Shiouji's Parents, and Why Excel's Player Feels the Need to Essay About Shiouji's Parents!