Fifteen days passed, and it was already the fifteenth day since the Zombie Apocalypse had started.
During those fifteen days, the zombies had evolved way too fast.
From Normal Zombies, the zombies evolved progressively to Elite Zombie, Special Zombie, Leader Zombie, and then Zombie King.
The powerhouses among zombies were mostly at the Leader Zombie level. Those at Zombie King could be counted on one's hand. Haley had also become a Zombie King powerhouse.
Of course, as the zombies have grown stronger, the treasure chests they've dropped have also improved in quality, allowing some survivors to acquire the Virus Evolution Manual.
Virus Evolution Manuals were divided into ranks that corresponded to the upper limit of the Evolver rank that it could guide the survivors with.
In Zayne's case, he had easily acquired an Overlord rank Virus Evolution Manual, which provided a detailed guide on how a human could become an Evolver Overlord.
