Thanks for asking! ❤️❤️So at first, Daphne is the one who welcomed Allison, but not because she wanted but because she had to. (Long story short, Daphne was one of the best student and was forced to welcome her in order to give a good impression). Anyway, at first, Daphne is lowkey cold and close to Allison and even more after she saw that Scott has a thing for her and vice versa. But Allison is way too kind and warm and Daphne started to open herself up to her. Allison is the first person that Daphne bond with since a long time, and the pair become close despite Allison is in the popular crowd. To Daphne, Allison is her first girl/best friend and like a sister to her. So when she dies, Daphne is broken as hell and have a very hard time to cope!
As for Allison, Daphne is the first friend she had in Beacon Hills. She wasn’t afraid by the coldness of Daphne and was determinate to gain her trust. Daphne soon become someone important to her because unlike Lydia, Daphne didn’t became friend with her based on her appearance but for who she was. To be honest, Allison is glad to have her as a friend because Daphne is always there for her, no matter what.