By first glance, Céline is very much a princess classic. She speaks often of joys, her gentle appearance and charisma makes it easy for her to make friends and her kindness comes from a desire to help others. She has a deep fondness for tea. Fairly curious, she often attempts to dig for knowledge in new situations, or when she is driven for a particular goal.
Heavy is the head that wears the crown, however, and she is all too keen of this fact. Even a kingdom as peaceful as Firene has its problems. Céline was trained at a young age to possibly succeed the throne, as her older brother had been sickly in her younger years. Further still, she had once been a crybaby, but her father's death early in her life sobered her greatly. Even though her brother's health eventually improved, the war during the game's timeline made her worry greatly about her brother's demise and the troubles visiting Firene's front door. With all of these worries, she shies away from things that make her truly happy in fear that they will eventually end and she will long for them, to the detriment of her responsibilities.
Because she cares deeply for the kingdom she hails from and the people within it, she will go to any lengths to protect it, even through ruthless ends. Her kind nature actually works as a great motivator for her ends that justify the means. It is also for that reason that she deploys diplomacy first and force second, and is never shy about wielding either. Even if the pressures of being royalty get to her, she is much too driven to not see it through.