She comes from a fallen noble family and was previously one of the Shield Hero's slaves. She is currently a resident of Rock Valley, serving as an instructor of the Hengen Muso style and helps the Legendary Heroes with their duties.
Rishia is a young girl with long, green hair, green eyes, and a rather petite figure. Her hair is tied into two braids with ribbons.
In the Light Novel, she often wears green clothes and a brown vest over a beige dress, brown arm guards, and boots. She also wears what appears to be a green cape with gold trim and red jewel button.
When she was in Itsuki's party, she often had simple armor covering her chest and shoulders. She would also sometimes wear an animal costume (first a squirrel, then a penguin, and currently a filolial) due to her shyness.
Rishia is shy, but extremely devoted and will go to extreme lengths to be useful to the object of her devotion. After Itsuki casts her out of his party for an act she did not commit, she is devastated. She weeps, and, believing that she was nothing but a burden to Itsuki, runs into the sea, hoping to die.
Even after being saved and recruited into the party by Naofumi and Filo, Rishia's admiration for the Bow Hero doesn't waver, and she hopes to continue growing stronger so she can be of help to Itsuki in the future.
Despite her clumsy demeanor, Rishia has proven to be a worthy addition to Naofumi's party. She was the one who helped Naofumi turn the tides against the heroes from the other world with the smart deployment of a barrel of Lucor Fruit (which renders people unconscious or weakened, with the exception of Naofumi due to his high resistance), and their fight against Kyo. She is also an adept magic-user, able to utilize all kinds of magic at a general level.
Later on, she is able to become extremely bold when facing great odds, confidently speaking what's on her mind and not holding back on what she believes. She shows this side when fighting Kyo and Itsuki for their respective injustice and cruel actions. However, after those kinds of battles, she would revert back to her shy and clumsy self.
Rishia was mentioned to have studied in a school at Faubrey until she was forced to discontinue her studies due to her family's money problems. Naofumi suspects that both Rishia and Malty might have studied in the same school with a few years between them. Aside from Gym, she had such good grades that she had trouble choosing what to major in. It is because of Faubrey's influence that she doesn't share the nation's negative bias against the Shield Hero.
Her family is technically noble, but they live in a farmhouse and not a mansion. They were tasked with governing a town. Though they were poor, they lived peacefully. They disagreed with a number of Royal pronouncements, which resulted in their authority chipped away. They learned of a neighboring town, Northern Territory, that was governed by a rotten Noble, who obtained their funds through illegal means. Fearing him, they started to raise their defenses to protect their region which drained the remainder of their resources. This earned the ire of the fellow men.
Recently, the fields, crops, and buildings in their town were sabotaged, and theft at night became common. Merchants and tradesmen stopped coming to their region. The neighboring Nobleman asked for their daughter in return for his help to them for their recovery from the situation, but they refused. Soon the burglaries increased. Even though they never asked for any guild assistance, a bunch of adventures chased away the bandits, and the bill was sent to them from the guild. Finally, their daughter, Rishia, was forcefully taken away by that Nobleman in exchange for half the fund and some bodyguards. Later, the bodyguards were revealed to be the same people involved in the robbery and the request to the guild was sent by the nobleman under their name. The evidence was erased and the couple was asked the same amount for their daughter's return.
That evening, Itsuki and his companions, who were investigating about the evil noble, came to know about Rishia and infiltrated the villainous noble's mansion, using the authority of the Hero to put an end to their dealings and save Rishia. Rishia felt greatly indebted to her saviors. To show her gratitude and support for her savior, Rishia would go on to join Itsuki's party. She would then be treated as an errand girl, carrying food and supplies for the Bow Hero's party, leaving her talent in magic unused and untapped.