Isabella has long, thick black hair, silver scales and fierce blue eyes. In Deep Blue, when she wakes her daughter up, she wears a grey sea-silk gown and her hair is piled high on her head. At the Dokimi, she wears a jewelled golden crown, a ceremonial breastplate made of blue abalone shells and and indigo, billowing sea-silk skirts and her hair is coiled at the nape of her neck.
Isabella is very democratic and cares deeply for her people, ruling Miromara fairly and ensuring she does the best for her realm. She is very strong-willed and has high expectations for Serafina, demanding perfection at all times. She is very intelligent as she is experienced in ruling and is loyal to her subjects. She is brave, like her daughter, and is not afraid of fight.
Isabella has very high expectations of her daughter, demanding perfection in everything she does, which irritates Serafina. She puts ruling first in everything she does, which exasperates Serafina. Often feeling disappointed with Serafina's lack of thoughtfulness, their conversations normally ended in arguments or awkward silences, but deep down, Isabella loves Serafina and is proud of her.
Isabella wakes up Serafina on the morning of her Dokimi, ensuring that she will practice her songspell. They discuss politics and the recent raids, before she scolds Serafina for not thinking. The argument ends when a servant arrives and tells her of another raid.While discussing whether to declare war on Ondalina, who are suspected to be behind the raids, she refuses to, not wanting to cause a war without the alliance from Matali, who will be attending Serafina's Dokimi.
At Serafina's Dokimi, she is hit by a poisoned arrow while the city is stormed by assassins. She was fatally injured but before she dies she is taken to the palace where she orders Serafina to escape to the fortress town. Serafina is reluctant, no wanting to leave her dying mother, leaving Neela with the only choice but to drag her away. She later dies upon her throne, due to the arrow being poisoned.
- The name "Isabella" is the Latinate form of "Isabel", which in itself is the Medieval Occitan form of "Elizabeth", which originates from the name "Elisabet", which is the Greek form of the Hebrew name "Elisheva", meaning "my God is an oath" or "my God is abundance".