|Date of Birth||April 1|
|Story Debut||Target 1|
Arina Luccini has long ash blond hair, green eyes and a mole on the left below the mouth. She is Luca's twin sister, Nozomi's tutor and she's seven years older than her. Arina has seen Nozomi's birth, she has always played with her and then she helped her with homework. Decimo recognized her qualities and her intelligence, despite her young age, entrusting her his daughter. Arina is wise and mature, she always has an answer for every problem and for Nozomi and the other she seems to be a big sister.
She and Luca were Stefano and Elisa's sons, they where killed during an ambush by a rival family that was very dangerous.Their maternal grandfather could not raise them and only Luca was given to a newlyweds, because they could not keep both. Thanks to the closeness between Stefano Luccini and Vongola family, Decimo decided to take care of Arina, taking her to the mansion when she was two years.
When she was child, she always went in normal schools like every other children. She moved in Japan when she was 15, following Nozomi, after the Lhumor Corp. incident. When she was 14 she loves a boy called Alessandro Demerito, but something happened and she was left traumatized and she never fell in love after him. She was no longer able to call Nozomi by her name after the incident, she call her by her title "Undicesima". She'd like to respect Decimo's will and see Nozomi living as a normal girl but she can't face Nozomi's resolution so she can't help herself and she follows her dreams.
She built them when she was in middle school.
- She seems to like Fukada Masato.
- Arina used to sing with Nozomi, when they were little. However no one, at present time, has ever heard her sing.
- Arina is the manager for the N.XI team.
- She doesn't hate her parent's killer. She seems to be a very merciful woman like Decimo. Perhaps this is why he decided to leave his daughter to her.