My Evil Spirit Can Be Synthesized Infinitely

This is an era of resurgence of terror. In order to survive, humans can only sign contracts with ghosts and use their power to fight against ghosts. When Su Yan traveled through time, he was also bound to a synthesis system. Able to combine different ghosts. "Congratulations to the host, for synthesizing ten Yin Soul-level ghosts and obtaining a Fierce Ghost-level ghost!" "Congratulations to the host, for synthesizing ten fierce ghost-level ghosts and obtaining a red-clothed level ghost!" "Congratulations to the host, for synthesizing ten red-clothed ghosts..." Su Yan: For others, this world is hell. But for me, this is paradise! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.