BWH:
75-52-77 cm
She is described by Yami as a "second generation" transforming weapon, making her abilities more advanced than her sister's. She has displayed several abilities Yami has never been shown to possess such as the ability to transform parts of her body into powerful energy weapons and even enter a person's (Rito's) mind while they sleep to extract information. The one similarity shown between the two is a preference for using their extremely long hair as a transformation medium.
Unlike her sister, Mea has never known anything in her life other than being a living weapon. Her first memories are of waking up in the rubble of the research station she was born in and meeting Nemesis, a living weapon from another project. She is there for very confused by her sister's choice to remain on earth living a passive life and though she does slowly come round to the idea she retains her opinion of herself as a living weapon and longs for her sister to embrace the idea herself.
Mea has a laid back and mischievous personality bordering on psychotic at times. She is rarely not smiling particularly in combat and acts friendly to friend and foe alike. She seems to enjoy messing with and teasing people, particularly in regards to Yuuki Rito and all the girls that have feelings for him.
For example she has made more than one reference to him having licked her body or her desire for to do so, though she makes this out as a joke. However it has been discovered by Oshizu (during her possession of Mea) that this desire is in fact completely genuine. It was also discovered by Oshizu that within Mea mind is a darkness so deep that it almost consumed her and has left her highly mistrustful of Mea ever since.
(Source: To LOVE-Ru Wikia)