At the end of the fight between Sora and Roxas, Roxas said,"You make a good Other." I thought "Other" was supposed to be technical term for the opposite of a Nobody, so why is everyone saying "Somebody"?

"Other" actually sounds good to me, I think I just use "Somebody" because everyone else does. And it's less confusing.

Somebody is a fan-coined term. When Roxas says other, he doesn't mean Somebody, more like as their two sides of the same coin, like in CoM when Vexen says Twilight Town is a memory taken from the other side of his heart, meaning Roxas.

i loved that fight after that i respected roxas and im sure xemnas or someone else said "somebody"