Honestly, I would probably be in the Order. Though I'm not a big fan of the Chief God(s) (which isn't to say that practicioners of the Chief God's religion aren't good. On the contrary, I admire it.) and would probably end up being an Elementalist, I can see the logic behind an Elementalist support behind the Order's goal. And so I would fight for the Order.
That is, until the inevitable occurs. I'm not even going to pretend it won't. Most Order soldiers end up being stolen away with or monsterized eventually.
IF and WHEN this happens, if I had a choice, I would prefer being with either a Hellhound, an Orc, an Ogre, (I would choose Holstaur but I'm not entirely sure they fight in the Demon Army, so the probablity isn't very high) or maybe an Ushi-Oni. Something along those lines. As for spirituality, Pure (non-monsterized) Elementalism for the win. Were I to believe this, my personal opinion would be that the monsterization of women and land violates the purity and sanctity of nature (the main goal of Elementalists are to keep Nature are pure as possible). Though the Order often weaponizes Elementals, it does not fundementally alter their state of being and is therefore morally justified.
It's an unpopular opinion, but hey, it's mine.