Her pink hair is less saturated and calmer than usual, tending to fade toward the ends. Her eyes also give off a deep, cool impression. She always maintains a somewhat languid or indifferent expression, possessing a mysterious appearance that blends well with the desolation of the "Empty Sekai." Rather than warm comfort, she employs a blunt way of speaking that hits where it hurts. She often flusters the Niigo members by blurting out the truths they want to avoid, though Kaito is an exception. While she wants to help the members, her methods are very unique. She has a 'mischievous' side, intentionally provoking them or watching to guide them toward finding answers on their own. While the other Virtual Singers tend to approach members warmly, Luka takes a position of observing and enjoying the situation from a step back. Rather than being kind, she is a mysterious and cool guide who watches without giving away the answers even when she knows them. She is a very charming character who injects tension into Niigo's characteristic heavy and gloomy atmosphere. She can be seen as languid but very good at delivering harsh reality checks.

She has purple hair and two-toned eyes of purple and light blue. Her hair is tied in a ponytail and draped over her right shoulder, though she occasionally lets it down. She is the only character in Project Sekai with piebald eyes. Except for the color of her pupils, she is the spitting image of her mother, and even then, the purple hue makes them look identical.

She has light grayish-brown hair. Unlike the other members of 25-ji, Nightcord de. who all have long hair, she stands out with a bob that reaches halfway down her neck. Her charm point is the braid on the left side of her hair secured with a small ribbon; it seems she did not braid her hair this way during her middle school years.

She has pink hair and eyes, styled in a side ponytail. Her pink eyelashes are also a distinctive feature. While there was initial speculation that the pink eyelashes were false, the fact that they remained even during middle school when she gave up on grooming and hid herself, and that her older sister also has pink eyelashes, suggests it is likely genetic.

She is characterized by pale skin, long straight silver hair, and pale blue eyes, with a small physique. She is one of the characters officially recognized as being cute.