They are childhood friends and have known each other for a long time. She was the one who appointed Kanata to be the instructor of E601 despite Freon's dismay. Even though other consider Kanata as a traitor Chloe seems to hold no anger towards Kanata and doesn't like whenever someone labels him as traitor. They were part of the same platoon called S128.
They used to be part of the same platoon called S128. Now they are both part of the Guardians, Yuri is the Vice Captain of the guardians while Chloe is one of the Guard Captains. They are very good friends but Chloe does admonish her when she says something against Kanata.
Chloe and Lloyd are very good friends. Chloe, Kanata and Lloyd have always been the part of a same team from the beginning, from when they were an E-ranked team to now a S-ranked team. Chloe and Lloyd are also the only people who believe in Kanata.
Fleon Flamel is the Guardian Leader of Mistgun while Chloe is the one of the Guard Captain. They both seem to be good friends and on Chloe's recommendation, Freon appointed Kanata as E601's instructor even though she hates him.