Maya Natsume (棗真夜) is one of the main protagonists in the manga and anime series, Tenjou Tenge. She is the younger sibling of the late Shin Natsume & the elder sister of Aya Natsume being the captain of the Juken Club.

She's able to use a  body manipulation technique that  to take the shape of an 8 year old girl to conserve her KI. Her ancient ancestor (with the same name as her sister), the feudal era Aya Natsume used a similar technique to have the opposite effect of allowing her to appear as an adult despite only being 9 years old.

" http://tenjoutenge.wikia.com/wiki/Maya_Natsume "