(Spoilers alert) So I've seen let's plays on Sonic Boom:Shattered Crystal and Rise of Lyric, but why does Shadow fights Sonic for no apparent reason.

Now now now sasha calm down Sonic boom más like a different universe i pretty sure he still the same in the modern original universe.

Hmmm I know that, but what's up with Sonic and Shadow. I mean sure they are from a different universe, but why do they just randomly fight.

Well tu know how Shadow he want to be better then Sonic but don't give me wrong o anything yeah sure becomes to speed yes true sonic has advantage over shadow but becomes to fighting shadow is better because he has huge advantages over Sonic so Shadow is a better fighter then Sonic is trust me i see the fact that shadow fighting has más skills then sonic is and he fights más brutal then him as well.