You weren't entirely sure if this would work, but you were used to taking risks. You weren't sure if this man, Lleaoflad, was in his right mind, but you were used to dealing with shady people. You were used to a lot of strange things, surviving in the Living Lands. However, grafting another's soul to yours was not one of them.
A while ago, you had met a man. A very strange and determined man, absorbed by his noted and research almost every waking moment. He seemed to need to find a way to escape the gods' cold, forgotten grip on humanity. His way of doing that was animancy. The magic of the soul.
After somehow getting you to agree to his experiment, he found a man. A weak, broken man, struck down from a promising career by poverty and the loss of several family members. In Lleaoflad's eyes, "One with a broken, fractured soul."
The procedure had been simple. Use some old, but still working animancy equipment to remove the man's soul from his body, then graft it to yours without pushing your soul out, having his soul possess your body, and not have either of our souls get lost along the way. You had watched the burst of essence come from the man's body, traveling through a machine, several tubes, and eventually, a very large tube above your head. You had known what essence felt like beforehand - just soul energy. But this had been different. It had been... alive.
Now, you weren't sure what to make of your situation. The man's body was dead, yet his soul lived on in you. It had been a success. But Lleaoflad only ever considered the potential improvements. Not that you'd be hearing the man's voice in your head every day, seeing wisps of his figure around every corner, even being able to use magic more effectively. He lived on in you, giving you - the both of you - more power in the strangest way possible.
Lleaoflad had vanished shortly after the experiment. He was never seen again.
One day, you were wandering through the woods. At your side walked the wispy, ghost-like figure only you could see.