We get the first indications that Young Sephiroth isn't socialized because he whistles to call over the others to his position. This is something he didn't know would be rude, which means it's also a learned behaviour.
It's most likely that this is how he gets treated. Given the relationship that Rufus has with Dark Nation commanding him with similar calls, this is something about the overall environment that Shinra has that's consistent and rather telling of how they treat those they're in charge of. It's why Glenn calls him a cyborg** at first for which he later apologizes.
**IMPORTANT: The term
Glenn uses when referring to Sephiroth as a "cyborg" is 改造人間, which literally means modified human, and it's an accurate descriptor for the SOLDIER program as we're classically familiar with it and isn't true of the P0 SOLDIER. This is different from how
Chadley uses the term サイボーグ for himself, which is literally just the work "Cyborg" in the more classical artificial human sense. While there is value in looking at the parallels between the rebellious Chadley being raised by Hojo in an isolated environment growing to turn against Shinra paralleling a lot of the same conditions of Young Sephiroth's upbringing, in addition to Young Sephiroth being 15 when this part of the story takes place – which is the exact same age that Chadley is portrayed as in
Remake. This is why it's worth making it clear that there is a significantly overt distinction between the two of them in Japanese that the English terminology can't smoothly differentiate.
Secondly is that he's combat trained but this is his very first actual field mission. That means that he's been using the Combat Simulators that
Crisis Core &
Remake established, and that he's also rather significantly isolated. The stories about him have been fabricated so that he can be their poster child for the new SOLDIER recruitment program since they're looking exclusively for candidates who have specific physical requirements as they're not going to stick to the P0 types anymore, but they're going to start the human modification with mako & Jenova Cells as the standard process (a big part of what the Green Match Tea team being P0 SOLDIER seems to be about highlighting). This underscores something else about Young Sephiroth is that he explicitly DOESN'T want to be a hero, and that it is just Shinra's propaganda pushing him into that role that he has no real interest in, because he's a just tool to serve as a means to and end for them.
This recontextualizes moments like his fight with Genesis (& Angeal) on the simulated Junon canon, as Genesis explicitly wants what Sephiroth has, but Genesis comes from a place of privilege being wealthy in Banora, so they don't see that in the same light as Genesis sees it as something like the award he won for making Banora White, whereas Sephiroth sees it from the cold perspective that Shinra does. That's also the event that leaves Sephiroth feeling disconnected from them as friends because of the (unknown to him at the time) compatibility barriers between Project G SOLDIER and himself as the Project S subject exacerbate the rift between the two of them. This is why Zack who wants to be a hero is the one who Sephiroth is always deferring missions to, because he can't figure out how to feel. Assumedly the cinematic prior to starting
The First SOLDIER campaign with Genesis not picking up is around the time of the SOLDIER mass desertion, and adding in even more weight to the strain of that which eventually leads to him telling Genesis to rot in Nibelheim (which I'll add more to in a second).
Most of this all helps to establish why Sephiroth is up for turning against Shinra together with Zack and refusing to kill their mutual friends, so long as he's got Zack to be able to defer to in some capacity. What's most telling though is that much like Zack undergoes a significant change prior to setting off towards Nibelheim, the Sephiroth who arrives at Nibelheim together with Zack is already VERY different from the Young Sephiroth who met up with Glenn, Matt, & Lucia when it comes to his beliefs about his own life. While we get some glimpses of that dynamic in
Rebirth's portrayal of Cloud's fantasy Nibelheim flashback in how Sephiroth talks to "Cloud" referring him him wanting to be a hero and calling him a puppy, as they're the sort of things that show that those little bits of humanity are still down there in Sephiroth seeing Zack as a friend... the biggest difference is how Sephiroth sees himself, which comes down to understanding more about WHO he is at this point.
This sequence underscores a number of things. First is that Young Sephiroth is the spitting image of Lucrecia, and the match of the look of their hair and facial features is
even more apparent in the cinematics where you see it in motion.
There's zero doubt that THIS is his mom, but it's also important to remember that at this point what Sephiroth's history would have been like. We know from the original game that Sephiroth's had a brief, positive relationship with Professor Gast which would have been limited to being prior to
Gast's disappearance from Shinra, and Hojo besting Hollander for his position – which had originally taken place in 1980. However,
the original opening cinematic for the non-Ever-Crisis version of The First SOLDIER showed some of that timeline a bit differently:
• 1977 is when SOLDIER Project 0 started
• 7/7/77 is when Jenova is (mis)identified as an Ancient
• 9/3/77 is when the Jenova project is approved
• 1977-1984 is when Gast, Lucrecia, Hollander, & Hojo were involved in carrying out a series of human experiments involving Jenova
• 1985 is when Gast was murdered & Ilfana was kidnapped with the infant Aerith
• 1988 is when Glenn comes to Matt's rescue while fighting against the Type-0 Behemoths, followed by Lucia saving both of them
• 1989 being when the mass simulated SOLDIER training environments were being used (
The First SOLDIER game)
• 1992 the events of the
Ever Crisis chapter of
The First SOLDIER take place
That places Sephiroth as being 8 years the year Gast is killed and makes it likely that whatever he learned from Gast being at the same formative memory age as when 7-year-old Aerith & Ilfana escaped Shinra HQ and her mother died. (Additionally, while Young Sephiroth was 15 in 1992 when this takes place, this is the same year when Aerith & her own mother Ilfana escape and I'd wager that Sephiroth having his first ever field-op may end up being related to the window of opportunity that allowed them to make it out without being recovered).
What's noteworthy is that at 15 we still see all Young Sephiroth's cautious optimism that he'll be able to have a normal life with his mom at some point, which is what he wants more than being a hero. After they have a brief confrontation around their awkward interactions, but before they start their mission Young Sephiroth addresses the other three,
"There's something I want to ask. Do you know this woman? Her name is Jenova." Lucia comments that she's beautiful to which he replies,
"She's my mother. You don't remember seeing or even meeting her?" and when Glenn states they haven't
"Right... Professor Hojo gave me this picture, but he wouldn't tell me anything about her. I know going around asking about my mother isn't cool..." "Anyway, we're almost at their base. Everyone, keep your guard up."
The most stark thing about this is that this VERY CLEARLY establishes what Sephiroth's go-to is in conversation for what matters to him. He's trying to get answers to questions that no one at "home" will give him, and Glenn assumes he's asking before the mission in order to make sure to effectively extract the intel from them in case they die on the mission – which Young Sephiroth mentions hadn't even crossed his mind. What this makes even more poignant is how this EXACT SAME THING happens in Nibelheim.
"So, how does it feel? TO be home after all this time? I have no hometown, I wouldn't know." and then Zack asks him about family and he INSTANTLY replies with this same thing,
"My mother's name is Jenova. She died shortly after I was born. My father..." but now he just starts laughing to himself and then cutting off from that with,
"Why am I talking about this? Come on, let's go."
At this point, it's been a decade since that mission and Sephiroth is 25. He's still the same person deep down, but he's essentially given up on ever being able to find his mom and have a normal life. He's been through the Wutai war while being trapped as the public hero of SOLDIER where the accomplishments of others get announced as his – like Zack's mission at Fort Tamblin not even mentioning his accomplishments, and the news only talking about Sephiroth. His friends have always been getting pulled away from him, he's disenfranchised with Shinra, and he's not even attempting to chase his dream anymore ...except that this is where that dream he's had his whole life actually comes true – but it's not a dream at all.
This is where the nightmare begins.
After learning that he's the product of a human experiment to create the perfect monster for Shinra to be the poster child of their SOLDIER program, and then
feverishly reading all about what was done there for a week straight seemingly without sleeping – he's crushed that Professor Gast never told him the truth about his mother, and that he died for reasons Sephiroth STILL doesn't know. He still thinks Hojo is nothing but a hack scientist in comparison and knows he can't trust him, but
now we know that he's also made to doubt the picture that Hojo gave him and who he'd been asking about constantly as a kid. And all of that is what eventually pushes him past the breaking point where he uses Ardent Flare on Nibelheim.
The Nibelheim Incident is LITERALLY his Limit Break.
The spike in both physical & magical attack power, the overt aggression and massacre of everyone else. He's gone totally insane, and he's singularly possessed by the drive to create a new world with himself and his mother free from all of the manipulation and horror of what they've been subjected to. And all of that is what it takes for Sephiroth to FINALLY have the resolve to go past that door and find what he's been looking for his entire life... and is put face-to-face with Jenova in her tank.
We know that
the lingering Jenova Cells within Lucrecia from having Sephiroth gestating in her womb wouldn't let her die, and that despite never even being allowed to so much as hold him, she dreamt of him constantly feeling unworthy to be called his mother. However, prior to this I hadn't really ever considered the possibility that the most haunting part of that relationship would be what Jenova is known before for – she takes the form of others and
the Advent Children opening cinematic shows that Jenova is ALSO the spitting image of Sephiroth AND Lucrecia. A picture of Lucrecia's face is what Sephiroth carried around with him but doesn't seem to have any more, and so he'd see the absolute worst version of what he could imagine – that face he'd yearned for his entire life attached to a twisted alien monstrosity of an inhumane lab subject kept preserved in a mako reactor, cut off from any human contact just like him.
Even more than that is on their mission after attacking the Rhadorans, Sephiroth's only injury sustained is from one of the child soldiers. He chastizes the other 3 for underestimating the young & elderly, and it's the young Cloud who kills him over that same pain of losing his own mother in Sephiroth's attack. It's this cold dissociative disconnection of the psychotic break that distinguishes the pre-Nibelheim & post-Nibelheim Sephiroth both in the personal pronouns that he uses, as well as his overall demeanor and why Zack doesn't recognize him as soon as he breaks.