[Kamen Rider] The Upgrade Item Is Actually Me

Hello, everyone. I've lost my memory.

That setup sounds awfully familiar, but I've lost my memory, so I can't remember why it feels familiar.

The only things I can remember are an astonishing amount of knowledge about cosmology and my name. Beyond that, I barely know even the basics.

Who am I? Where am I? What am I supposed to do...?

All those questions were answered the moment I met the first Kamen Rider.

"Wizard! Magician!"

"Synchronization starting. Checking compatibility!"

"100%! 500%! 1000%! Perfect synchronization... Super perfect!"

I fused with Kamen Rider Wizard, whom I'd just met.

First-person narrative.

1. There are a few very minor Lovecraftian elements.

2. None of the original characters knew the heroine before she lost her memory.

3. A wish-fulfillment story, with multiple love interests to choose from. No outline, just writing as I go, and canon couples are broken up.

4. Most of the plot involves the movies and side stories. I don't feel like writing the TV series...

Theme: Even if I become a part of you, I won't lose myself.