Kara lived the first part of her life entirely unaware she had once been someone else. but, after failling to escape from krypton, the trauma of getting trapped in a ship makes her fully remember her previous life.
Now she must strugle with two sets of memories and make sure her little cousin is gonna be ok, knowing everything the DC universe can throw at her she knows even being a Kryptonian won't be enough.
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The world is mostly Young Justice but I won't deal with the team all that much.
MC has the memories of a young guy from our universe but she was trully reincarnated and has lived most of her life as Kara Zor-El without any memories of her previous life. It's best to think of it like an amnesiac who has built a new life suddenly remembering his past memories.
Fellow beings of refined taste, after 37 chapters, there is finally SMUT! Still, Smut will be separated into its own chapter, and can be easily skipped if you don't really want to read it!
This is something that came to me once and just wouldn't leave so I had to write it down, I also have a Danmachi fanfic and a Smut Xover if anybody is interested.