>>534045380
Underground ended on a whimper. Sonic Universe was supposed to resolve it but Sega rejected the idea halfway through. The fanmade Archie preboot had a decent idea to wrap it up, but in all honesty Sonic would go "hey fuck Robuttnik but y'know what also fuck Monarchy, Sonia can have that fucked-up shit if she wants, Manic you can do whatever but I'm gonna wind off so see ya."
Also I swear some of the background character look as out of place as the minor STC characters, but if you look at the show we almost got instead (Sonic Sisters in Space) it suddenly makes sense.