Tatsumi: She acts as an older sister to him, as he calls her "Nee-san". Leone enjoys working with Tatsumi and seems to finds great joy in his company. She is also shown to worry about him as he is "Too kind". As the story progresses, she seems to develop some romantic feelings for Tatsumi. She often shoves his face into her breasts, and even saying that she will claim him as her man when he becomes a little older (by marking him with a lick on his ear). The two can laugh at and with each other the most among Night Raid. Both share one of the closest relationships within Night Raid.
Akame: The two appear to be friends, but their relationship is sometimes used for comical effect, seen when Leone punches her when she comments on the difference in their weight. Leone claims Akame to be her best friend and often acts as an older sibling to her.
Lubbock: He is often caught trying to peep on Leone while she is bathing. Most of his attempts end with him getting beaten up by Leone herself.
Chelsea: Chelsea and Leone got to know each other quite well during the short time they spent together. They teamed up to tease Tatsumi, asking him whose swimsuit looked better.