Doomsday Zerg Devouring System

One day out of nowhere, the zombie apocalypse engulfed the world. 
Liu Han was a simple office worker who fought to survival until he was known as the strongest human killing god. 
While he and his comrades fought the decisive battle with the Corpse King they were betrayed by their commander all for the sake of elevating his son to a higher status. 
Liu Han watched as all his comrades died just moments before he took his last breath.
To his surprise, he woke up in his old office while seated in front of his desk. 
He then realised that he had gone back in time a few moments before the zombie apocalypse started. Suddenly, he heard a familiar voice in his head. 
“Dark Insect King System activated”. This is the voice of the system that previously helped survive the apocalypse in his previous life. 
With hatred of his betrayal still lingering in his heart, he was prepared to take revenge against the one who betrayed him and his comrades.