Magical Girl's Knight Brother

Because of an accident, Tang Zijun traveled to a parallel world.
Also traveling with him was an unknown Kamen Rider Belt.
After realizing that there was a strange other world called the Mirror Plane hidden beneath this world, Tang Zijun, alone, spent several years successfully eliminating all the monsters in the Mirror Plane.
At the same time, he is gradually adapting to his new identity.
Just when he was living the peaceful life he wished for, Tang Zijun accidentally discovered his sister's secret - she was actually a magical girl!
Is there a camp in this world that even he doesn't know about?
Are there more than one evil monster in the mirror plane?
Am I going to have to watch my sister live the same crisis-ridden life I had before?
In this regard.
Kamen Rider Tang Zijun, who has been retired for seven years, reluctantly picked up his belt again.
"Don't blame me. If you want to blame someone, blame yourself for picking on the wrong person."
"henshin!!"
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