Amalla Su is Kaolla Su's sister.
Amalla is the older sister of Kaolla, both being princesses in the island nation of Molmol. Following their father's death, Molmol was taken over by the grandfather of Lamba Lu, who adopted Kaolla and Amalla into his family. When Kaolla was arranged to marry Lamba, she fled the country due to not having any romantic feelings for her stepbrother and took up residence at Hinata Inn in Japan.
Amalla appears to be in her 20s; having tanned skin, long white hair and blue eyes. She is dressed in Molmol island attire with a purple tubetop and long white skirt.
Amalla has similar tomboyish traits as Kaolla, but without the energetic demeanor her younger sister possesses. She has a magical flute that allows her to control the weather and a pet albino alligator named Shiro.
Amalla would make her first appearance in the anime when she caught word of Kaolla triggering her adult form. Under the assumption that Keitaro was triggering the transformation due to his physical resemblance to her brother confusing her, Amalla would abduct him and attempt to seduce him to try making Kaolla lose interest in Keitaro. However when a fight between Amalla and Keitaro takes place, Kaolla would come to realize that her brother wasn't Keitaro and would return to her regular form.
Amalla would appear later on to try having Kaolla commit to her arranged marriage with Lamba. However, she was unaware of her sister's lack of romantic interest with her stepbrother and was repressing her own romantic feelings for her stepbrother. Kaolla would persuade Amalla to confess her feelings to Lamba, leading the young prince to apologize for being oblivious to Amalla's feelings. It was implied that the two would go on to later marry and return to Molmol.