Mélie's relationship with Seth is very strong, since according to her, only he can get her out of a mood change crisis. She respects him a lot and puts a fist of honor on him being her friend. After their first meeting when Seth rescuers her from the Inquisition, they join forces since Seth doesn't seem bothered by her infection, and go on their first mission to Rumble Town together.
She is shown to be very fond of him. It is when they return to Artemis where Alma tells Seth that Mélie watched over him during his long sleep. This is seen again by the pain she felt when she finds out that Seth left to Caislean Merlin and deliberately left she and Doc in Artemis not to endanger them. Following this, a cold settles between them, quickly erased by the urgency of events in the castle.
Doc sees Mélie as a source of trouble, as almost any sorcerer that met her. He knew her before Seth arrived on Artemis and was already working with her as her Tracker. Despite the fact that he doesn't want to cause problems, he finds himself constantly traveling with Mélie after the events in Rumble Town, especially since he became a child because of his infection.
Their relation became so deep that Miss Melba, the waitress of the Artemis (whom Doc is in love), takes him for Mélie's son when they return to the Institute after the war in Caislean Merlin.
At first Mélie consider Grimm an enemy because of a misunderstanding on his side, but after it is all cleared, she seems to consider him an ally and begin to rely on him to help them when they feel in need.
Mr. Boobrie is Mélie's pet. He follows her constantly and never leaves. He has a connection to her infection since his personality is inverted too. He constantly attacks Mélie, except during her crises where he becomes adorable with her and probably masochist since he is very motivated to the idea of taking a beating of her.
It is not known, however, whether he is himself a part of the infection or if, for some reason, he was able to connect to Mélie's crises.
As Mélie joins the Apprentice Squad of the Sorcerer-Knights she was able to meet Ocoho. When both realise they acquaintanced with Seth, they immediately create a connection. Despite having a good relation with her, Mélie is often bullied by Ocoho, as she usually hangs Mélie to scold her.
Despite working for the Inquisition, Dart seems to hold a care for Mélie as he saved her from the Nemesis in Rumble Town and even helped her escape from getting caught by Liselotte in Caislean Merlin. His true intentions with Mélie and Seth are unknown.