Unscientific Ghost Raising System

I have an inexplicable system that requires me to raise "ghosts" in real life and then use their power to increase my strength. But the key point is that modern society has long entered the Age of Ending Dharma, and the spiritual energy of heaven and earth has been exhausted by humans. Where is there sufficient spiritual energy to ensure the birth and survival of "ghosts". No, it's still possible, so if there really is a ghost... It must be... This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.