Helldriver

Kika and her father hide from her mother, Rikka and her uncle, Yasushi, both serial killers and cannibals. They are found in an abandoned town, and Kika's father is burned alive. Before the homicidal siblings can kill Kika, a meteorite hits Rikka, punching through her and destroying her heart. Still alive, Rikka rips out Kika's heart and puts it in her chest. Immediately after, an unknown substance encases the two, putting them in cocoon-like states. Black ash emits from Rikka and eventually covers the northern half of Japan. People who inhale the ash are turned into bloodthirsty zombies. In an effort to contain the infection, a large wall is erected, dividing Japan in two, keeping the zombies north while most of the uninfected population remains south.