"I swear that child is a demon." It's no wonder that the patron of Yusnaan thought that of the tiny trickster girl, though many of the other citizens of Nova Chrysalia apparently make light of her penchant for mischief. Her interactions with Lightning are less "mischievous" and more "randomly antagonistic", however, but that may be because Lumina is a part of Lightning; the part she rejected in order to be what she considered strong. Lumina has a skill for sticking her nose where it doesn't belong, in the name of help. And while some of her meddling does have a golden lining (she procures the coffer of souls so that Sazh can restore his son's soul, as well as points out that he needs to be less sad and mean if he wants his kid to return) there are somethings you just have to go "what the hell, Lumina" (such as when he purposely gives Noel an oracle drive with a fake prophecy of him killing Lightning...) though it's likely that Lumina sees even her more... rude stunts as "helpful" in their own way. She's very much a big picture person over little details.

And Lumina does mean to help-- well and have fun, as she states herself. She is far from a normal child, and clearly considers it her job to in particular check-in on Lightning's friends (including being there when Fang and Vanille were freed from crystal, pestering Snow enough that he thinks she's a demon, etc) while Lightning was, y'know, missing for five hundred years. That said, Lumina has a habit of seeing the world and the people in it as her playthings, so to speak. While she has a desire to help others, she is very playful and incredibly unpredictable. When she appears to Lightning, it's usually to taunt her or summon monsters for the Savior to fight. Despite her clear dislike of God (aka Bhunivelze), it could be said that she has a habit of playing God herself-- or, no. Rather, she plays snack-sized guardian angel. The residents of Nova Chrysalia seem to regard her mischievous antics lightly. To be fair, who could hold anything against such a sweet face? (Snow Villiers didn't seem to be a fan, but it could be that it's the weird resemblance to his dead fiancée throwing him off. Or that Lumina has just been a brat to him.)

While not a normal child, she is a child. Having fun is clearly a priority, even if it's followed closely by whatever tangled up help she gives others. She is easily amused, not surprising since she often has the upper hand. Some of her "helping" antics barely seem that at all-- giving an oracle drive with a false prophecy to kill Lightning to a guy, trying to convince Lightning to kill Snow to put him out of misery-- but they are. Lumina has a good understanding of those around her, of the humans that she toys with most. Of course, by that time she had been running around for five hundred years, so it's not entirely amazing. Though she seems to be the only one who's gotten anything done in all that time, even if most of it could be summarized as "general mayhem and mischief".

Lumina is the part of Claire Farron that Lightning wanted to be rid of-- "I'm Claire Farron. Her selfishness, her loneliness, her fear. That little bit of your soul that you couldn't accept." And these are the traits that make up Lumina's core; a selfish, lonely, and scared child. Lumina is not Lightning and Lightning isn't Lumina, but both of them are Claire Farron. Both of them care for the same people, in particular Claire's sister Serah. It's no real wonder that Lumina toys with Lightning like a cat with a mouse, considering that she knows the woman best and could be a bit hurt by Lightning essentially tossing her away like trash-- and she only reintegrates once Lightning realizes she doesn't want to be sucked into the Chaos and left alone, in other words once Lightning sucks it up and stops trying to reject her emotions.