It's like everyone in this world is a retarded psychopath that gets off on being the biggest edgelord possible.
Yeah, yeah, the guardian spirit talked about how the "Battle Song" software(?) or whatever that gives... gifts or whatever the fuck they're called... messes with you (albeit she wasn't too keen on the specifics and whether it's a chemical or physiological change or what and WHY they have decreased empathy - there's tons of people that love the thrill of an adrenaline rush and find themselves drawn to warfare/combat like a moth to a flame and they don't randomly massacre innocent people, so...), but this is just breaking suspension of disbelief and becoming absurd.
Like, why the fuck would the Sage who is apparently there to work to protect the train just stop by and murder the passengers there? That'd be like your bodyguard having a tussle with some dude and stopping to kill their principal employer because it sounded fun and edgy. Even teenage edgelords that want to murderkill everything would realize that killing the people that you're employed to protect probably isn't a good idea. At this point I'm wondering how the fuck these Sages and the kingdom(s) don't collapse into complete and utter anarchy because of retarded OP psychopaths going on random killing sprees and trying to murder one another because of egos, distrust or megalomaniacal aspirations.
The fact that, quite bluntly, the art sucks ass and is a mess in many places doesn't help this manga at all. Then again, why waste good art on a story and worldbuilding this lazy?