I played this game around 2010 or so, at my brother's Windows PC. It looked like PS2-era 3D graphics, but I don't know if it was in any other platforms. Decidedly western in style.
The story was a war between Heaven and Hell (or demons and angels), and "spirits" or "ghosts", which were caught in the middle, as a neutral faction in Limbo/Spirit Realm or somesuch.
With each faction you played as a low grunt in the first stages (like an imp for demons, for example) and as you cleared stages, you played as increasingly powerful and more important figures, until you reached playing as their leaders in important events.
It definitely was a third person action game with combat. I THINK it might've had some light Real Time Strategy elements as well, giving orders to NPC units.
The spirit/ghost/neutral faction leader was a bald man with glowing white eyes, and a yellow/golden sword. But I might be confusing him with the angel faction's leader, unsure.
Two distinct vivid images I have was the faction select screen with the demon leader's 3D model in the left, the spirit leader in the middle, and the angel in the right, standing there, menacingly. Another one was the demon/hell faction's first stage, in which you were an imp, in a group of a dozen or so others, following orders. It was striking, and very, very cool.
I've tried finding this game before to no avail. Perhaps I didn't research enough, but there are so many games about angels and demons fighting that I couldn't for the life of me find it, each time I tried.