BALDINTEGRA

Okay, so. Both themes and lore are similar yes so I'll start with lore. Forsaken Murderer was an inmate sentenced to death for murder and later used for experiments, which made him into what we see him as now (will get to that). Meursault was also an inmate, presumably will be sentenced to death (judging by the thing director showed us), presumably for murder (in the book it's murder. but also in the book they sentenced him to death and not exile, so who knows what Limbus does with the crime). His test subject status is unknown, but he definitely has something to do with Canned Experiences (which btw is a Singularity just like Cogito is/was). He might have been force-fed them as punishment or something. Both of them were judged for not showing remorse, regardless of whether they actually felt it. Both of them have a connection to Carmen/Ms. Sun, Forsaken Murderer was experimented on by her team, and Meursault seems to have Distorted in the past, and he is connected to the Sun in general. I don't think we have any more lore on FM so can't speak about that, I will say though, his metal head reminds me of prosthetics users and the way he's afraid of it reminds me of how prosthetics are demonized in N Corp. so he might have connections to N Corp. or be from N Corp. like Meursault (also note that Carmen seems to have connections to N Corp. as well)

For themes... Ohhh. I will say how I view Forsaken Murderer: at least as an inmate, he felt regret for murders he committed, but it proved to be too much so he started pretending to be an emotionless heartless killer (I say this because in the artbook it says he has "massive regret", his damn E.G.O is named "Regret", and also all lines from him sound like he's putting on a show for others, anything but seeming "pathetic" or remorseful) but eventually, after the Cogito experiments, he was just left with his regret and empty rage/hatred/abhorrence (the things Yesod says chained him down). I operate within this conclusion. Additionally, his Abnormality form might represent what he saw himself as more than who he actually was... I don't know though.

Meursault also at least appears to be an emotionless murderer, however, in the book it's stated that he just does not pay attention to his emotions, but we see him expressing them without acknowledging the emotions themselves (consider his relationship with Marie as well as him lashing out at the chaplain). Which is... interesting. I won't say he feels regret right away but I think he's at the very least not emotionless. This may be supported by the face he keeps getting IDs of highly emotional people (Lei Heng, BHK, Camille, etc.). So both of them probably have repressed emotions

Speaking of IDs, Meursault keeps getting IDs of people who had something happen to their heads/had been executed or at least sentenced to it. His head is kind of his focal point (even in his Base E.G.O, look at the shadow). Same with Forsaken Murderer both literally (his metal head) and metaphorically (the disease of the mind Carmen and co. tried to cure). Both of them had something happen to their necks, Meursault is sentenced to be guillotined in the book, and Forsaken Murderer attempted to hang himself in prison which is why he seems to have a broken neck

Both are shackled by something, Meursault is metaphorically bound by chains of others (how others see him dictates how he sees himself and acts and what he is put through, hell is other people) and Forsaken Murderer is literally bound by the straitjacket (though it might also be metaphorical, maybe he's still showing some self-restraint despite the rage and violence... wishful thinking)

From here on I think it's best if I paste things from another rant because I put it better in there:

Both of them seemingly have something to do with "judgement": Meursault refuses to enact his judgement, presumably due to having made a mistake in his judgement in the past, and Forsaken Murderer's judgement is kind of impaired in part, due to his delusions (such as his metal head)

Both of them are connected to rot; Forsaken Murderer's flavor text says his brain was left to rot, and Meursault's associated color is called Decay Blue

Both of them have something to do with the Experiences-Memories dichotomy. Forsaken Murderer is, arguably, only experiencing: he's "chained to the resentment and hate of the past", but he doesn't remember what he was "forced to see" (Regret Angela's lines). Abnormalities work in a way that they will forget all information that contradicts their vision of the world. With Meursault it's unclear what his deal with Memories/Experiences is, except the connection to Canned Experiences

Both of them are connected to light/darkness: Meursault states he prefers daytime over nighttime, because "what's hard to see is hard to understand" (LCB Sinner Meursault's chatting lines), but what's important is that he prefers light over darkness. Forsaken Murderer's Containment cell is stated to always be "dark and cold" and his brain is said to have been "rotting in darkness" (flavor text). He might dislike darkness because of that (though he hates when his Unit is changed so???)

I thiiink that's all I have? Unless I am forgetting something. But it's still a lot I think. I am very passionate about this topic.

Anyway, I think if PMoon didn't see these parallels and doesn't confirm them or make them pay off with a Forsaken Murderer appearance, I will be disappointed. If not in Canto X, at least in an Intervallo or in a Walpurgisnacht he kind of HAS to appear because this is genuinely an insane amount of similarities

They're both so very interesting to me, and I really hope to see more of Forsaken Murderer. I want to see if I am right. Even if I am not I think he's my favorite character in Project Moon, even more than Meursault maybe