Here are the characters from every universe that involves in the story.
Sonic universe
• Sonic the Hedgehog
• "Miles" Tails
• Knuckles the Echidna
• Shantae universe
• Shantae the half-genie girl
• Clone Wars universe
• Ahsoka Tano
• Captain Rex
• Halo Universe
• Master Chief
• Cortana
• Uncharted 4 universe
• Nathan Drake
• RWBY universe
• Ruby Rose
• Weiss Schnee
• Blake Belladonna
• Yang Xia Long
• Final Fantasy IIV remake universe
• Cloud Strife
• Tifa Lockheart
• Barret Wallance
• Aerith Gainsborough
• Red XIII
• Legend of Korra universe
• Korra
• COD: Modern Warfare 3 universe
• John Price
• John "Soap" MacTavish
• Yuri
• Nikolai
• MLP universe
• Twilight Sparkle
• Rainbow Dash
• Applejack
• Bioshock Infinite universe
• Booker Dewitt
• Elizabeth
Wolfenstein universe
• BJ Blazkowicz