Goddess of Fortune

Ji-yun is a perfect high school student who has always lived in the shadow of second place. After discovering a mysterious notebook that grants her unbelievable luck, she finally becomes the top-ranked student she always dreamed of being. But her newfound fortune comes at a terrifying cost when her friend Saera suddenly disappears from everyone's memories. With the help of fellow student Dohun, Ji-yun must uncover the truth behind her cursed luck before more people vanish forever.

(Source: Webtoon Entertainment)