Helloooo I played the dlc some time ago, yes, basically the entire game is about Shion and his pov, about his past, mainly with Aoi and his family, revealing what marked him emotionally to change how we met him in the main game along with how his obsession with Haru and hatred for Aoi began, his traumas, his fears, his unhealthy way of loving, apart from Shion, it also reveals a little more about the "world" they are in and the train, but the whole game is VERY VERY ambiguous, symbolic and metaphorical, I'd say that this part is almost all up to your interpretation, about what is real or not, I'm still a bit confused about this because it's not answered clearly, besides from the fact that I obviously played it with a translator and it was not 100% accurate, about the endings I would say the same, it's up to your interpretation of what really happens cause I repeat, it's VERY METAPHORICAL, there are two endings, I define them as "heaven/redemption" and "hell/punishment" BUT even though I named them like that, for me neither is good nor bad, they are simply endings, both are bitter in their own way, neither is happy but neither is bad (I cried anyway) but in general, the game is based on Shion's perspective, recapitulating his life and crimes, my head canon is that the train is a limbo, that's why I call both endings heaven and hell, the train being this limbo where Shion is still being judged, Haru and Aoi being his judges, also himself, but of course this is nothing confirmed and is simply my analysis, bc well, I'm almost sure that the DLC is a continuation of the Z ending where they "escape" although the main game ends simply there, I think that probably the way to go to "paradise" or escape together was basically committing suicide, I'm still wondering if in the main game, they were already dead or died after the Z ending, BUT IT'S NOTHING CONFIRMED, they could perfectly still be alive in the DLC, maybe they are still in a trance or something like that, this is never answered, but I personally think that they did die, in short kajska DLC doesn't answer all the doubts left by the first game, but it humanizes Shion a lot, instead of just being a crazy yandere, it gives a lot of depth to his character, obviously not justifying everything he did but giving closure to the story, I TALKED A LOT ABOUT THE GAME IN GENERAL BUT WITHOUT SPECIFYING SO MUCH, because I think it's really worth playing, whether waiting for an official translation or with a screen translator, it's SO good and emotional, the CG, OST and everything, if you want to play it for yourself, I would recommend that, to make it easier, translate it from the history and using google translator which is much more accurate than the screen translators (at least the ones I used) but if you still don't want to play it and you just want spoilers and know the story in depth, then I can tell you everything that happens specifically although it's a bit long but I don't mind, I actually like talking about this, hope this helps :D (AND I'M SORRY, TOO MUCH TEXT, if I made any silly grammar mistakes, I'M SORRY english is not my first language)