I use she/her pronouns for Ruka.
In the end, Okabe isn't the only one affected by their time travel experiments. Although they don't remember as much as he does, all of his friends feel the lingering effects of the changes they made. The shifts occur differently in each individual, but the result is the same: they've all become different.
Moeka is overjoyed to have made new friends and found a steady job. Finally finding people who accept her, despite her fear, has made her happier than she can ever remember. But she's terrified of her dreams, because in her dreams she kills the little one, Mayuri, over and over. They're more like nightmares, really, but the worst part about them is that they always feel so real.
She doesn't understand why she keeps dreaming about it, but it's starting to carry over into her real life. She finds herself apologizing constantly to Mayuri for the slightest things, trying to absolve the guilt lodged deep in her heart. Mayuri just seems startled and confused by her constant begging for forgiveness.
She's also developed a deep abiding hatred for guns, which also seems connected to her dreams—unsurprising, really, since in most of them she shoots Mayuri in the head, killing her instantly. Her newfound fear of black leather and motorcycles is less easy to explain. In the end, Moeka just does her best to ignore the dreams and move on. She's finally achieved some peace and stability in her life, and she won't allow her subconscious to destroy that.
At first, Daru isn't too affected by what happened. He has the occasional nightmare of Mayuri dying and of being captured by a strange group, but those taper off quickly. He becomes a little more wary and paranoid when he hacks into systems, but he writes that off as him finally growing up and being a little less reckless.
This all changes when his daughter is born. Holding her for the first time in the hospital, Daru gets a sudden feeling that she's in grave danger. He begins to have nightmares of his daughter fighting in a rebel group, or even worse: he dreams that he leaves little Suzaha and Amane and goes off on his own, leaving his wife to raise their child on her own. He talks about it with his wife; she chalks it up to the worry and stress of being a parent for the first time.
Daru knows that there's something more at work here. He cradles Suzaha in his arms, calmed slightly by holing her. "I'll never leave you and mommy," he murmurs to her, rocking her slightly. "Never ever." She falls asleep to his quiet litany of promises.
Both Ferris and Ruka hold strong memories of their experiences on the other worldliness. The memories show up as fragments in dreams, at first, but soon both girls have remembered everything. Ferris grieves her dad again, losing a bit of her ever-cheerful attitude. She has a memory full of experiences she had with her father, another life where she didn't grow up as an orphan. The grief is strong and sharp.
Ruka grieves for the future, not the past. She remembers her date with Okabe so clearly, how magical and wonderful it was. She knows that in this life she'd never have the courage to make it happen, and the grief is like a dull ache in the back of her mind. At least, she muses, she can still be around Okabe. They're still friends, even if that's all they'll ever be.
Mayuri doesn't understand why she's suddenly so afraid. She hates her dreams, and how something awful always happens to her in them, but she hates how they affect her more. Moving cars, loud noises, the subway, and even certain street corners and alleyways in Akihabra are suddenly terrifying. Part of her wants to ask Okabe about it, but she doesn't want to make him sad again.
The strangest thing that Mayuri notices is that she's wary of Moeka, which is ridiculous. Moeka is timid and kind and would never harm her—but in Mayuri's nightmares, she tries to kill her, over and over again. Mayuri doesn't know why she keeps dreaming about that, but she does her best to shake off the dreams and move on. They have so many new friends now, and it's silly to dwell on bad dreams when real life is going so well.
Kurisu retains vivid memories from the other worldliness—her dying in a storage closet, Mayuri dying in various horrible ways, finding Okabe crying on an overpass, and, embarrassingly, kissing Okabe in the Future Gadget Lab while rain pours down outside. She does her best to ignore the dreams, but no matter what she does they seem to keep coming. She resolves to ask Okabe about them next time she sees him, even though she knows she'll probably get some extremely weird answer involving time travel.
Eventually, they all talk to Okabe, and he explains to them as best as he can about the time travel and alternate worldlines. They believe him, to varying extents, but that still leaves it up to them to decide how to move forward. In the end, they all do their best to forget, and move on with their lives. But the residual effects of time travel still linger.
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