|“||Please believe me. I believe, I know you never committed any crime. You gave me medicine, saved my life and taught me what I needed to survive. You are the great Shield Hero, and I am your sword. No matter how rough the path, I will follow you.||”|
She is the first real companion of the Shield Hero. Although she was originally bought as a slave, she was never treated badly and forged a strong bond with her master.
She later travels to another world and obtains the Vassal Katana, becoming the Katana Hero (刀の勇者 Katana no Yuusha?). Additionally, she becomes the Heavenly Emperor of Q'ten Lo after overthrowing the previous emperor.
She has undergone some significant changes throughout the story. When Raphtalia is first introduced, she is a child with long, unmanaged hair and a dirty cloth gown. After being purchased by Naofumi, he gives her a haircut to an acceptable length, gives her a bath, and buys her a much more suitable set of clothes to adventure in. As a mixed-race of Raccoon and Tanuki, Raphtalia is shown to have fluffy dog-like ears and an averagely sized bushy tail.
After several weeks of travelling with Naofumi, Raphtalia's body inexplicably changes and she gains the appearance of a beautiful young adult. It is revealed that demi-humans initially mature in relation to the progression of their levels, which leads to Raphtalia's rapid development.
During their travel to the Glass' World, L'Arc mentions to Naofumi that Raphtalia has reverted back to her child-self when her level is been reset to one and she has to grind to reach her adulthood in that world before reuniting with Naofumi. In her adult form, Raphtalia begins to wear clothing much more fitting for a warrior, which consists of a hide breastplate, skirt, lace-up boots, and a pair of gloves. Raphtalia also switches from a small knife to a full-sized sword during this time.
Raphtalia is initially very shy, sickly, and fearful as a result of her status as a slave, as well as suffering from trauma with memories of the destruction of her village. After the encounter with the two-headed dog monster, she overcomes the trauma of her parents' death at the hands of the Cerberus and acknowledges Naofumi as a hero in her own mind.
Naofumi acknowledges the strength of her heart. Despite been through a lot for her age, from seeing her parents die, to being sold with her fellow survivors, to seeing her best friend tortured to death beside her, she manages to maintain her morals and sanity. She hopes to reestablish her village and fight for the country that wronged her kind. This causes Naofumi to take up his role as a hero seriously and help her in the reconstruction of the village.
She desires for Naofumi to act as a hero and is disappointed by many of his actions. The current Raphtalia is focused on efficiency, in both combat, training and money expenditures. Seeing this trait, Naofumi feels that he brought her up wrongly, as she doesn't show any girly desire for her appearance or care for efficiency. She is extremely devoted to Naofumi and harbors feelings for him which he remains oblivious to, preferring to see her as his 'daughter' he raises her in lieu of her deceased parents. As she matures, Raphtalia not only becomes much more skilled and deadlier in battle, but she also gets much bolder, opinionated, stronger-willed, and fiercely protective of her beloved Naofumi.
Until the age of 10, Raphtalia lived in a small coastal village outside of Melromarc, where everyone lived in harmony until the first wave of calamity attacked. During the attack, Raphtalia and her parents fled from their home, but considering they could only dive into the sea to escape the monsters, Raphtalia's parents made the ultimate sacrifice. Her parents pushed her off a nearby cliff as the wave approached them and she watched as her parents were engulfed by the Cerberus. Raphtalia survived the fall and went back to find her parents, but was unsuccessful. Shortly thereafter, a group of Melromarc Knights came to her village and killed all the adult survivors. They captured all the young ones and sold them to the slave hunters for money.
She and many of her friends ended up being purchased by Idol Rabier, who pleasured himself by torturing the innocent demi-humans. Raphtalia suffered and witnessed her best friend die, which caused her to have a mental breakdown and left her traumatized. Afterwards, she was sold multiple times until she ended up with the slave dealer in Melromarc. Alone and sickly, she was picked up by a slave merchant and put up for sale in the capital of Melromarc. Raphtalia was at the slave traders for weeks until she was purchased by Naofumi Iwatani, at which point her life would be changed forever.
- Her bond towards the Shield Hero has reached a point where she can often tell what exactly he is thinking with just his facial expressions. She often points it out and scolds him when he thinks of something very unreasonable.
- Raphtalia has a strong dislike for the Raph species, she finds it strange for a monster to be based on her genes.
- In the Web Novel, she possesses the Vassal Hammer rather than the Vassal Katana.