Chronicles of the Holy Empire

An ordinary young boy was sent to the Death Fortress to fight demons. He grew up in blood and tears, became strong in life and death, and became famous in the fortress. But when faced with the intrigues in the imperial capital, the cold and belligerent princess, the gentle elf, and even the cunning and charming female devil, how will the young man make his choice? Where are the devil's minions lurking?