Core of Darkness

"Core of Darkness: Book 1. A rogue sorcerer and his demon slave are plundering castles and laying waste across the mythical Western Kingdom. But it's more than gold and jewels Yara's searching for - it's enchanted relics. Using a stolen forbidden ancient spell, Yara can absorb a relic's magic to his own core, making himself a little more powerful. Bit by bit he is becoming the most powerful sorcerer in the world, crushing all those who stand in his way. Although magic has been outlawed, it may take another sorcerer to find and defeat Yara and his demon from Hell.