Oh No, Brother Zheng Caught Me as a Bug from the Start

The main character, Xue Bufan: a wage-slave programmer with little hair and an endless supply of dirty jokes. His motto in life is: if you can lie flat, never stand; if you can talk big, never throw a punch. Then he stepped wrong and the System sent him straight to the Qin Empire to help it with its technology. The other main character, Ying Zheng (Brother Zheng): the biggest client in the world, the ultimate workaholic, and an obsessive-compulsive to the extreme. At first, he sees Xue Bufan as a walking, human-shaped bug. Later, he realizes this bug is actually pretty great: a super patch that can upgrade the Qin Empire straight to the next version.