Universe CAV-4

Also known as "Chaosverse", CAV-4 is the setting for the fancomic "Chasing Velocity" and is a clusterfuck of headcanons and plot ideas created by mathonwys! Compared to the other universes discovered so far, CAV-4 is pretty different from most versions of Mobius when it comes to the cast and history. Notably, the resident Sonic is a bio-engineered science experiment based off of recovered documentation from Project: Shadow that was created by Christopher Thorndyke (and also happens to be a trans girl), among other huge deviations. It still seems to have more in common with JRH-5 than BLM-10 does, though.

While the "current time" of JRH-5 is a couple decades after the war to take back the planet, on CAV-4's side of the Bridge it's only been 5 years since Infinite's defeat. Sonic has a bit of trouble getting her head around the fact that the other Sonic has a daughter that's the same age she was when they met.

Interestingly enough, CAV-4 had incidents of multiversal travel years before the formation of the Bridge: Blur the Cat and an alternate Jordan the Hedgehog got sent there after a run-in with Metal Scourge, Copy made the jump after hearing about it from Blur, and years later a younger version of a Sonic was accidentally dragged here from the Twilight Cage by Infinite. It doesn't appear to have a corresponding "Sol Universe", though.

The most well-known residents of Chaosverse, besides Sonic herself, are probably Sik, Double, and the other members of Team Horizons and Team Comeback. It's also the home universe of Seven and Vance.