Left to right i think
**this comment contains spoiler.
the story talked about yuki being deranged because of the poisonous gas from 15 years ago. i think there are two ways we can take it, first is that the chemicals of the gas got into his body and affecting his genes/brain (basically like secondhand smoking). the second could also be trauma from witnessing such a terrible event in the past. i think both reasons are why he is messed up.
also, his brother was not in it with him. when they were on the plane, he pretended to be his brother which is why he got away and his innocent brother got killed instead.
Since the story has 0 comments i'll be the first to...
This story is well about deranged guy who got that way due to some pass incident or so they say and I don't think thats it... Now there is this priest who gets caught up in this guy twisted tale due to something he did to the other long ago...
My opinion is that this is just a twisted tale about a guy who gets away with absolutely everything like this guy (slight spoiler) might have gotten exposed to toxin so said messing him up but I don't know I think there is something else like a mental illness due to something that happened in the pass not sure what but thats the case and I think he teamed up with his brother not sure but maybe.....(ENDING SPOILER)
The priest die and I don't know how it happen but the brother was on the plane and I seriously believe he either team up or somehow use his bro as a decoy so he could escape twisted but to be honest I somehow liked it... End.