Airi Arcadia/Relationships

Lux Arcadia
As her only remaining sibling after the downfall of the Old Arcadia Empire, Airi loves her brother and trusts him, even though these very feelings aren't displayed directly to Lux.

Noct Leaflet
Noct is Airi's roommate and a fellow first-year, as well as her best friend. The two are often seen together and Noct regularly watches Lux on Airi's orders to ensure that he doesn't do anything perverse, much to his exasperation. Noct later confesses to Airi that she loves her brother as a man, prompting Airi to start planning a scolding for Lux for monopolizing the feelings of all the women she knows.

Nulph
The prime minister of the New Kingdom who has closely watched the Arcadia siblings closely after the former empire's downfall. One of many Airi's biggest concern is the New Kingdom trying to exploit Lux to protect the kingdom from harm.