Based on a joke in SWR. Aya goes into the Scarlet Mansion looking for a scoop, runs into Remilia, says something like 'As I walked into the Scarlet Mansion, I was assaulted by an evil creature!'. Remilia plays along with her until Aya says 'the creature screamed "Moke~"', at which point Remilia said she couldn't play along anymore - drops to normal conversation, then battle. I don't know what moke- is supposed to be, I assume, from the picture, that it's the sound an ostrich makes or something.
I don't think this is a spoiler, right? Story mode is straightforward enough... Also, I'm running off memory here, so my explanation may not be perfect.
