Curtosey of the peeps at
HJU...it's Hirata Yuka. Also known as MELE-SAMA!!!
I love her...*ahem*"feet parts", if you get what I mean.
EDIT: Just got caught up to Den-O 46.
So it was Nee-san all along?
I wonder if the losing her memory thing was to protect the timeline or something like that so that it wouldn't be completely erased?