Jennifer Portman is a crazy American super-scientist who came to Japan to study the "Extended Definition", a species' ability to prevent its own extinction, which usually manifests itself in said species transforming into a monstrous form that maximizes its combat potential, and gives it the instinct to attack or kill Hikari. She moves in with Takeru, Hikari, and Mari. She's rarely to be seen without some kind of alcohol and is somewhat of an exhibitionist. Although out of work she appears ditzy and idiotic, she is extremely intelligent at her work.

from wikipedia