HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

I'll say it again: we put the Breath of Death on top of the Armageddon's Blade and we can play the missions and campaigns of Armageddon's Blade in HD. Plus, we can play the missions and campaigns of Breath of Death, which, in my opinion, is not bad at all).
Therefore, we need the files for Breath of Death. Most likely, we can get by with just h3bitmap.lod and h3sprite.lod (~170 MB), but I'm not sure.