Reason: English name to Japanese name of the character. Both tags are inconsistently used; most have both tags, but some are tagged with just Akuma, some just Gouki.
It seems needlessly confusing to me to prefer the Japanese name for one character and the English names for others. It's more consistent to use the English names for all of them.
Hmmm you're right with that. But if that the case, we are using the ENG names for the pokemons but JP names for the characters. Still, I vote for the JP ones. Personal preference.