huh, the comments are surprisingly negative? Am I the only one who enjoyed this?
Anw I think the story is pretty easy to understand. This guy died and reincarnated, but due to his unfortunate look, he was sent off to be a slave, and then the slave contract basically manipulated his mind and somehow erased his past life memories. The other slaves also got manipulated and all of them were "nice" because the contract made them so, not bc they were really good people. But then shit happened, and they returned to the assholes they were, which resulted in total chaos.
Also, I think it's a bit too quick to blame the sister, we didn't even know what she is like without the slave contract. Also, since slaves can't use skill slots, why did 2 of her slots are used?? I'm sure there is a reason for why she did what she did. Or maybe the author just sucks at writing and made her leave for plot convenience