Originally Posted by maximilianjenus
Also, most of rika's "powers" coem from her knowing what happens until she is killed by takano, after she avoids that she knows nothing of the future.
Rika's ability to stop time doesn't come from that though. Hanyuu is really weak, but she does have some supernatural abilities that Rika appears to be able to tap into to an extent.
Bernkastel is simply the accumulation of memories from all the Rikas that have died over the past century that have become self-aware. I think what happens when "Rika" arrives in a new world is that a copy of (most of) Bernkastel's memories replaces the existing Rika's memories (Rika can't recall anything from before she was playing with the rest of the club members in Minagoroshi-hen or from before she was hit with a ball in Saikoroshi-hen), which explains why Rika is aware that a version of herself exists in a higher dimension, why she says that she isn't Rika when she's speaking to Rena in Tsumihoboroshi-hen (since Bernkastel feels that way to an extent) and also why she gives herself the name Bernkastel in Saikoroshi-hen to distinguish herself from Rika. When Rika dies, these memories join the accumulation of memories in that higher dimension and thus become part of Bernkastel. This would explain why Bernkastel retains the name that "Rika" came up with in Saikoroshi-hen and why the Rika in the world at the end of Saikoroshi-hen says that the version of her in the higher dimension no longer matters, since her memories won't be joining it when she dies.