For the first order of business, the next party member needs a name. Here is her bio, except for her name.
Hair: Blue, always pulled back into twin pigtails
Occupation: Priestess of Ariana
She will be the party's main healer/buffer. Her fighting abilities will be almost nill, so (spoiler) she needs to be kept pumped full of spirit potions. Being a pacifist, she only carries a weapon for self-defense.