Lasli is a character from The Legend of Zelda: Breath of the Wild. She is a Sheikah who is the granddaughter of Nanna. She works as a greeter during the day at the Enchanted clothing shop of Kakariko Village in the West Necluda region.
During the day, Lasli stands outside the clothing shop, Enchanted, to attract customers with the promise of new clothes.
Despite being a young woman, Lasli's grandmother insists she stay indoors at night due to the threat posed by monsters and Yiga Clan, which have become more active since Link's awakening. This means that she runs home at 9:00PM to sit by her sleeping grandmother. During this time, Link can release fireflies for her (If he's solved all the other sidequests in Kakariko Village) to gain a Purple Rupee.
In Kakariko Village's Journal of Various Worries, she goes by the alias Struggling Shop Girl and in her entry she writes how her job at Enchanted has helped her numb the pain of not being able to hunt for fireflies at night as she had been asked not to walk around at night as it's dangerous, but that the only thing that makes her feel better is walking among the fireflies and doesn't know if she can cope without fireflies.
After completing the quests "Find the Fairy Fountain" and "Flown the Coop", Link can visit Lasli's in her house at night. She gives the quest "By Firefly's Light" requesting Link to bring her 5 Sunset Fireflies. After obtaining five of them, Link must return to Lasli's house and release the five fireflies inside her house and she will reward him with a Purple Rupee.