Karl Edward Wagner 
Dark Crusade [EPUB ebook] 

Kane the Mystic Swordsman encounters an ancient cult of evil. The cruel cult of Sataki has come to life again, and Orted Ak-Ceddi, a daring outlaw, is its prophet. Orted knows he must have a powerful cavalry to launch a new drive — and Kane is the man who can command the conquest. But Kane intends no final victory for the Forces of Darkness — he intends to rule the earth himself!