Originally Posted by Palsa

Yeah, that's a good suggestion, especially since some parts seem to be pretty empty.
If I manage to find more of her over the week, then I might try experimenting a bit with upgrades, but before then I think I'm going to send a quick message to Nutaku's support, at the very least to make sure that they're aware of her presence in the game.
On a side note, does anyone whose played the other version of the game recognize her?

I don't think a support ticket is necessary. The discord has been posting about her bug a lot in the issue reports so they're definitely aware.

In the DMM version she came out in Event 71 along with a new 3* and new 4*. However, we skipped that one and went to Event 74 first (cuz it's the Christmas event). So, she exists as a possible mission reward in the Event missions because of that. It's just an oversight by the devs to allow her to be obtainable that way.