EDIT: In general there actually are laws against killing them. Sparta declared war on the Helots about every year, because killing just like that, openly, for no reason, just raw murder, was just too gross. Just the level of cruelty. Even in the American South there were laws that said if a master just can't get a slave to submit, he's tried everything (I can't get an authoritative quote on this, what I'm giving you is the desert island version[1]), then in that case, the master can kill them. But I think it doesn't say kill, it's some other word. Of course, that's the law, the reality is different, the limit is far too low but there is a limit. Super basic stuff and difficult to prove, but for another example masters couldn't practice Satanism with their slaves, we're talking like egregiously egregious stuff. Which does occasionally happen.
[1] The desert island version of a text is what you remember without being able to search for it online, or review your notes, nothing. Like if it were you and I, dear reader, on a desert island, the Bible is what we remember, that's it.
[1] The desert island version of a text is what you remember without being able to search for it online, or review your notes, nothing. Like if it were you and I, dear reader, on a desert island, the Bible is what we remember, that's it.