Surviving The Doomsday With System

After traveling through time, he arrived on a completely different Earth!
Five hundred years ago, a colossal crisis erupted where a deadly purple mist appeared in the atmosphere. When humans inhaled this fog, they transformed into zombies, and animals became terrifying mutated beasts!
A few people who avoided this gas began their genetic evolution and came to possess all kinds of abilities. The remaining humans relied on these people to establish different bases or large organizations.
Now that he has arrived in a world where the danger of life lurks everywhere, he was suddenly bound to a System! 
A Powerful and Rewarding System called the Zombie Synthesis System! 
And the System's sudden appearance had made him incomparably happy and excited as previously he had nothing else to rely on but himself!