"We achieved something like this in 1944. Those fascists thought it was spirits…" The doctor continued babbling. He also revealed the method to deal with this ghost.
Since the ghost couldn't exist separately without a body, it needed a host, which was why it had two consciousnesses.
What the main character needed to do was to shut off the life-support system of its host, Billy.
A simple example would be in the 'Wind and Cloud' TV Series. In it, the Sword Saint's physical body died first when he used Sword 23, and that was why he wasn't able to kill Xiong Ba.
Now, the main character had to destroy the physical body of this ghost to kill it.
Usually, it wasn't something that an ordinary man with severe injuries and poor physical conditions could do. However, since the ghost had two consciousnesses, and one of them was willing to help the main character despite its short periods of existence, this task wasn't impossible to do.
