talking about it
akuma/gouki, gouken and evil ryu/kage designs are some of the most interesting for me
because they rely heavily in shinto imagery, that is syncretic with hinduism and buddhism...
lot's of possible interpretations and inspirations

evil ryu alt as fuujin

oni as raijin
(insert here akatsuki quote)

The 12 heavenly generals of yakushi buda are actually in sf4 temple stage
But their chief (kubira) have a different meaning in shinto syncretism compared to buhdism, as he is indentified as the same entity as the god konpira
He have a striking resemblance to akuma, no?

In sf3 akuma received a new super move, kongou kokuretsuzan....starting a association of him to the temple guardians kongōrikishi.
In sf4 gouken come in with his counter move kongoshin, associating him to the other guardian of the pair.

They are portrayed with a very specific format of belly, very different from western art as seen in those statues in Tōdai-ji temple (nara).
Oni is sometimes portrayed with this format of belly, and so is this rejected design for akuma from sf5 artbook

svc chaos art actually put shin akuma and mr karate directly in the same pose of those statues (but with looser belly)

going back to the line of syncretism
Acala was probably used as inspiration for this Kage alt.
But the thing is that in japan, due to shinto syncretism with buhdism he also have a slightly different interpretation, being identified with one of the kongōrikishi with closed mouth

Another alt and concept that reference the guardian statues. More emphasis in the clothe than in the belly tho

this Oni alt makes me a little lost.
It might reference acala as kage's alternative costume. But it might also be a rasetsu/rakshasa.