One thing I don't understand, and probably won't, is how this kind of "memory lock" just side steps basic psychology.
You're telling me that twins, individuals who have gown up together since they were in the womb, wouldn't recognize one another? Hell, just looking at someone face is all it sometimes takes to have dementia patients recall past memories.
We're told that her memory seal isn't perfect, then we should have gotten a few pages where Towa starts to recognize Kuro.
Holy hell I'm annoyed at the required suspension of disbelief that I have to have in order to let this plot line continue...