Alexander the Great invaded the Achaemenid Empire in 334 BC, successfully conquering it and dying in 323 BC. After his death, his Empire fell apart starting a series of wars called the Wars of the Diadochi. Considering that all of Alexanders generals had a portion of the largest Empire in human history up to that point to call upon, it seems likely that the casualties from such a war would be massive.
Are there any sources on the total casualties of this war? Are they in the thousands, tens of thousands, hundreds of thousands? More? Was it anywhere near, say, the Warring States period in China?