After I Die, I Transform Into a Martial Arts Demon

Humanity lost the war. Businessmen who sold out their fellow compatriots, hunters who turned to the monsters, stepping on countless human corpses, all in order to earn profit. The otherworldly monsters that entered our world seized it bit by bit like a raging fire. That was until Zuo Chi arrived.
"Back then you all were gladly invading our world, so why are you weeping now?"