The sunny boy from Cardcaptor Sakura

Cardcaptor Sakura fanfiction, not a crossover, single-world, pure love, lighthearted, funny, slice-of-life.
Q: What if I woke up one day and turned into a child?
A: Of course, I want to become a sunny and cheerful young man!
Xia Yu covered his eyes with one hand, a wicked smile spreading across his face: "At the pinnacle of humanity, I reign supreme over the world. With me, Xia Yu, the heavens reign! I, Xia Yu! A magician hidden in the mortal realm. In this magical world shrouded in the veil of everyday life, I am one of the very few chosen ones who have glimpsed the truth, holding the sun and moon in my hands and plucking stars from the sky. There is no one like me in this world, hahahahahaha!!!"