She has a very relaxed, upbeat, and cheerful personality, and tends to display a lack of ladylike manners, often seen shoving Tatsumi into her breasts, putting her feet on the table, or consuming large amounts of sake. She serves as a sort of big sister figure to Tatsumi and younger members in Night Raid, often referring to herself as "onee-san". Despite the morally dodgy nature that she sometimes displayed, Leone is not one to tolerate injustice, and can be especially vicious to those who commit the most vile of acts. She also enjoys fighting her enemies a lot, as said by Najenda who told her that she needs to change that habit.
Legends of the Multi-Universe: Armageddon
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, but this has yet to be confirmed, as she has yet to declare anything of the sort. 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. The two can laugh at and with each other the most among Night Raid. Both share one of the closest relationships within Night Raid.
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.
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 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.
Leone meets Black Star in Legends of the Multi-Universe: Armageddon when Black Star and Naruto were looking for the Underground. They officially met and introduced themselves while Leone worked to spy on Hugo Strange. Unlike most members of the Underground, Leone likes and enjoys hanging out with Black Star. She finds his attempts at hitting on her funny and cute. She also enjoys hearing Black Star tell tall tales, even though she knows they aren't real. She's also impressed when he was able to save Gotham from being destroyed.