Romance System Made Me the King of the Apocalypse

GoodShort synopsis

"In the apocalypse battlefield, mercenary Ethan awakens the weakest Love System ever. But the target bound to his system turns out to be Emily, an SSS-rank high-level mutant zombie. A handshake earns fresh meat, a first kiss grants a vaccine, and a bond unlocks a genetic evolution serum… While others can only upgrade one ability at a time, Ethan can obtain every resource by taming a beautiful zombie. As her affection level skyrockets, the savage beast gradually bows before him, yet her gaze grows increasingly dangerous and passionate. With the Love System, Ethan rises to become the ultimate ruler of the apocalypse."