I Was a Side Character, but Became the Protagonist's Grandpa

[Mindless wish fulfillment + face-slapping + no System] Mo Xuan, a man from Blue Star, transmigrates and becomes the protagonist’s golden-fingered old master. He then helps the protagonist grow and quickly become a powerful cultivator. The protagonist, Qin Fen, is the family good-for-nothing, with no cultivation at all. Everyone picks on him and mocks him. After meeting Mo Xuan, the protagonist’s path to a comeback begins. Mo Xuan, a man from Blue Star, knows the plot and helps the protagonist become powerful in no time. [This book is made up, and so is the plot.] Mo Xuan is a supporting character, here specifically to help the protagonist. Qin Fen is the protagonist, and he’s the one who will make a comeback.