MaestroRage on Newgrounds has some pretty unique and powerful war themes, and you don't need to fiddle around with YouTube downloaders.
I suggest, from the dozens(possibly around a hundred, haven't checked since Newgrounds kept messing up my IE a few months back) of songs he makes, "An Ambitious War," "Blood Fields," "Dark Skies," "The Spread of Chaos," "The Tanks Thunder," "Victorious Day," "Apocalypse," "Heroic Darkness," "Hundred Years of Pain," "Rage of the Champions," "The desire to Destroy," and "Thirst for Blood."
Two of those, "Dark Skies" and "Rage of the Champions," are in Castle Crashers.
Also, there are a few others...
Gravey has three "Orchestral Theme" pieces that are really good. The first two are good for any battle, but the third is more suited for Angelic and Demonic sort of things.
TheAmateurAnamator has a something called "TAA - The Final Battle." It's a Techno, unlike the others. But it's still pretty good, I think. There's also "Midnight Strike," a more conventional War movie theme.
XGM-Zeth has one piece called "March of the Damned," also like "Midnight Strike" is a suited for a War scene.
Gravey's Orchestral Theme. Get it from Newgrounds.
Nonono forget you I said it first.
