You thought it was some character get reincarnated into a game type of story. It's not.
Spoilers about the final act For starters, the world is fucked thanks to global warming and climate change. There were attempts at figuring out a way to help humanity but little to show outside of an AI named TAIM to assist the efforts of a real Claire and Lene. Enter Rae...or rather Rei Ohashi, who was researching conversing waste into a type of energy source that she dubbed Magic. Rei offered the idea of the "Eternal Loop System" where the minds of humanity would be placed in a simulation that will flip between a magic based world and a technology world and use resources from both sides.
Rei was planning on leaving after she laid the foundation because she didn't want Claire to know she was a lesbian. However, Claire pushed a relationship as a desperate attempt to keep Rei around and being pushed into it by higher ups. The relationship blossomed and improved and Rei wanted to have Claire join her as an administrator for the project after it was put into motion. But, Claire ended up dying from a sickness that was festering inside of her without her knowing. Rei chose to prematurely start the project to save all memories and brain movements that Claire had and planned to keep an eternal loop where she would be with a human representation of Claire and then start a new loop. However, Rei didn't consider one mistake that cost her. While Claire's memories would reset with each new loop, Rei's didn't. So, Rei was gaining experience in what to do and Claire was suspicious that Rei was fooling around with multiple women before they met and eventually had the two break up. Afraid of losing her memories of Claire and now seeing the world she built as useless, Rei decided that she'll kill Claire once and for all and shut down the world entirely. So, she created a Demon Queen persona, gathered all the demons and planned her assault on the world.
So, where does this leave Rae Taylor and who she is? It turns out she's one of a couple of clones of Rei built by the AI, TAIM, itself as an attempt to be a means to try and stop Rei from completing her plans. TAIM also made sure to leave Rae without enough memories to try and complete that eventual future mission.
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Asocial, not introverted. Know the difference. In a capitalist society, money and life are one and the same.
Yeah, lol, all along it was a science fiction story! :D
I loved the surprise genre shift.
Also you're not quite right about one thing, the reason they stopped being together was that Claire kept being mentally reset but Rei wasn't, so Claire more and more seemed childish and immature to Rei, and the spark in their relationship went out.
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Time is a funny thing, you know? I guess in the big picture of my life, you were only a blip. But oftentimes, those "blips" make the biggest impacts.