In her previous life, the self-sacrificing saint died beneath the claws of a mutant beast. Reborn before the apocalypse, Yan Ping vowed not to be a saint this time. But then the System arrived, and it actually wanted him to preserve the seeds of human civilization. Wasn't that just asking him to keep being a saint?
Yan Ping: Be a saint? I'd rather be a dog!
System: Host may choose to disconnect from this System. The penalty is death!
Yan Ping: …
System: Host, saving people brings generous rewards, and you'll even get special abilities.
Yan Ping: I'm in!
Yan Ping: System, killing scumbags doesn't break the rules, does it? Kill one to save hundreds or thousands. That's immeasurable merit.
System: …
Yan Ping: System, what happened to those generous rewards you promised? You didn't pocket them, did you?