This story is a sequel to A Mega Blast from the Past
Twilight Sparkle, along with her friends, family, the Cutie Mark Crusaders; minus Dinky, and her new Mobian friends end up back in the time where the Mobians ended up. But the ponies became Mobian versions of themselves. They would have to wait a while for the Time Machine plans to be finished, so they have to wait a while until the Time Machine is finished. If they might be in the past, Twilight might as well do some research while she's in the past.
Nyx was created by Pen Stroke and Joshua was created by jkreader
Get ready to meet the fastest thing alive!
"Sonic's the name! Speed's my game!"
Wait, uh, who is Joshua?
what? no chapter focusing on guard and flurry?
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Read this:
https://www.fimfiction.net/story/112906/new-life-in-equestria
Is Shadow in this story?