Not so thematic methinks

[theenemy]

Correct me if I'm wrong, but should the Deva be available as a pretender for Yomi?

[Herode]

Why not ? Is it its Hindu flavour that bothers you, or the fact that it's a demon slayer ?

[Rytek]

Perfectly sensible for a race of bully, headstrong demons to worship a Goddess dedicated to their slaughter. Not all worship is based upon good and love. I would guess fear and self preservation would be a great motivator for the Oni.

[JimMorrison]

Originally Posted by Rytek

Perfectly sensible for a race of bully, headstrong demons to worship a Goddess dedicated to their slaughter. Not all worship is based upon good and love. I would guess fear and self preservation would be a great motivator for the Oni.

I think he's more wondering about the Deva - why lead these uncouth, disgusting demons in conquest, when they're your ultimate enemy?

[Herode]

A prey is not an ennemy. And she will slaughter them in love

[Coldshard]

They are merely a tool used for assention.. after that they can be dealt with properly.

[Poopsi]

"demon" is just a PR/POV label. the other side's gods and spirits are demons

[Wrana]

It's good and well to label something as "label". :P But in this game's context it's a term with perfectly clear sense: something that's unholy by its nature, but isn't undead.
A part about demons worshipping a demon-slayer goddes is already answered. About Hindu origins of the goddess herself - I don't remember clearly about any Kali-like figures, but a lot of Japanese and Chinese mythos gods and spirits are of Hindu origins. And many-armed warrior spirits are certainly depicted in Shinto temples often enough.

[VedalkenBear]

but a lot of Japanese and Chinese mythos gods and spirits are of Hindu origins

Out of curiosity, do you have a source for this? As far as I know, very little is known of 'pure' Shinto belief due to the Japanese penchant for syncretism combined with the fact that written language was introduced to Japan hand-in-hand with Buddhism around 500 AD.

Further, Shinto zinzya is normally translated into English as 'shrine' and not 'temple'. Even moreso, every depiction of multiarmed 'spirits' that I can think of offhand in Japanese religious settings is actually Buddhist, not Shinto.

Since my information seems to be quite different than yours, I would be grateful if you could provide sources for your statements so that I can check to see if my understanding is correct. My own source is the Japanese curriculum in the Department of East Asian Languages and Literature at Ohio State University.

[Wrana]

First, what is wrong with your approach is that you think that there is "pure" Shinto belief. Shinto IS sincretic in its very nature, just like religion of antique Rome was. And as religious activity of Chinese common folk still is. It had always accepted gods, saints and spirits of foreign origin in its cult. So yes, multiarmed deities ARE of Buddhist origins. BUT they are still worshipped by Shintoist and depicted in Shinto temples (considering "shrines" - I used "temple" here as catch-all category, but am aware that large temples are mostly Buddhist. Still, Shintoist worship in them, too. I can't say for sure whether Shintoist ceremonies take place in them, but given a nature of Far East religious sincretism, this wouldn't surprise me.)
My information is based on both literature (Ovchinnikov, Abaeve, partly Torchinov) and my contacts with some orientalists in both Moscow and St-Petersburg Universities. You can doubt me on the basis that they are mainly Sinoists, and I'm more interested in China, too, but nothing I know indicates otherwise than what I said. And your mistake seems to be not in some obscure Japan specifics, but rather in basic premise.
To HoneyBadger: mainly yes. It's not quite correct to use "good" and "evil" in respect to this mythology, as it doesn't use such terms itself. Such creatures act to restore a harmony when the balance is tilted and there is a threat to universal order. But this order isn't "peace and love" and a threat to it may come not only from the direction commonly percepted as "evil". And Buddhist religion also includes Mara, who is deity of deception and relatively close to some perceptions of Christian Satan. I don't remember offhand whether any servants of him were mentioned, but such wouldn't surprise me. And of course, term "demons" is used in western translations due to the fact that Jesuits used it first after seing depictions of such creatures...