Heretic Spellblade - K D Robertson - Bog

Before the demons invaded, Nathan had everything he ever wanted. Women, power, magical talent, wealth, a fortress full of loyal soldiers.
Now, a beautiful demonic general offers him a choice: die; or start a new life with her in the past and rewrite history. Nathan accepts and is sent back in time to before the end of the world began.
Everything Nathan earned in his original life is gone. But he still has his years of knowledge and experience. Even better, he knows what will happen in the future. He doesn't know why the demons sent him back, but he refuses to waste this opportunity.
Nathan will take back everything he once had. But first, he must stop a demonic invasion from ending the world.
Heretic Spellblade contains plenty of violence, harem/undefined relationships, beast girls, and scenes that don't fade to black. Consider yourself warned.