[DaBackpack]

Originally Posted by Cao Ni Ma

First one

Spoiler:

I think the game is leading us to believe that the particular sin is having forgotten a promise and who ever was wrong going slightly more insane than before. I still dont think this is the actual sin though, just the given truth that leads us to believe it. I for one would not love a person that murdered my whole family just because I told a child whilst I was a child that I would come and rescue her. Call me cruel, but the yan type of lover is not for me.

I personally think that it is the forgotten promise idea between Battler and Shannon, but that does not mean that the forgotten promise is what causes the deaths.
If I remember correctly, Beatrice in EP4 says that because of Battler's sin, a chain reaction of events leads to the death of everyone on Rokkenjima.

So perhaps Shannon/Yasu said/did something to another person that he/she would not have done if he/she wasn't so upset by the broken promise. It is a chain reaction, but it's more like dumb luck on Battler's part.

Comparative to Higurashi, when

Spoiler for Higurashi:

Keiichi gives the doll to Rena instead of Mion, which ultimately leads to Shion going crazy and killing people. If Keiichi gave the doll to Mion, that entire series of tragedies could have been avoided.

This could be directly comparable to that: since Battler's sin is off of the gameboard (it happened six years ago) it will never be fixed, and thus the events on Rokkenjima are bound to happen anyway.