"Bloodlines of the Unknown"- A witcher tale

In the ruins of an ancient laboratory, buried beneath centuries of dust and forgotten history, a man awakens—his body that of a mutant warrior, his mind a storm of memories that are not his own. Once a simple human from another world, he now bears the instincts, knowledge, and power of one of the first Witchers ever created—a prototype lost to time, deemed a failure, and abandoned to rot in the darkness.

I only own the story, not the characters or the world.