You Don't Want an S-Level Bone Dragon, but You Choose a C-Level Zombie?

In a world invaded by demons, humans need to make contracts with the undead to survive. Wang Yu, who came from time travel, gave up the S-class Bone Dragon King and other powerful people on the contract day and chose C-class zombies, which was ridiculed by everyone. In fact, he bound the system and the zombies turned out to be generals with immortality. Relying on the system tasks and the power of his generals, Wang Yu's strength rapidly increased, he defeated doubters, joined the demon hunting group for experience, and then entered the elite genius training camp. After experiencing level challenges, curse troubles and genius duels, he broke through levels and slayed demons along the way, moving towards a stronger person, determined to protect mankind and settle grievances.