Rinoa Heartilly

Rinoa Heartilly is the female lead of Final Fantasy VIII.

Background
Rinoa Heartilly (possibly born Rinoa Caraway) was the daughter of General Caraway of the Galbadian Army, and Julia Heartilly, a famous singer. When Rinoa was five, Julia died in a car accident, and her relationship with her father was rocky. She eventually left home and started an anti-Galbadian resistance group in Timber called the Forest Owls.

Rinoa first meets Squall Leonhart at the SeeD celebration ball, where she convinces him to dance with her. Her purpose for being at the ball was to convince Cid Kramer to let her hire a small group of SeeDs to help her group liberate Timber from Galbadian occupation. The three chosen were Squall, Zell Dincht, and Selphie Tilmitt, and according to the contract between Cid and Rinoa, they were to be bound to the Forest Owls until they liberated Timber. Because of this, Rinoa joined the party, along with her faithful dog Angelo.

Rinoa's personality is everything's Squall's is not: Fiesty, compassionate, warm and friendly, and these traits annoy Squall to no end at first. However, opposites attract, and through the course of the game, they became closer.

After an attack on Edea at Galbadia Garden, Rinoa received Edea's (and Ultimecia's) powers and became a sorceress. Ultimecia possessed Rinoa and made her open the seal to Adel's tomb for the express purpose of possessing her. After the seal was broken, Ultimecia left Rinoa for dead in space, but Squall rescued her.

Rinoa=Ultimecia?
The Rinoa=Ultimecia theory (aka R=U) is quite popular in some circles, but is only based on circumstantial evidence at best and possibly not intended by the developers.