Fantasy: Take Back Your Sister's Immortal Eyes at the Beginning!

[Traditional fantasy + no system + multiple training systems + single female protagonist + fairy knight] Lu Xuan, the eldest son-in-law of the Yun family, awakens the bloodline of the demon king in order to regain his sister's immortal eyes. "A demon pill is swallowed into the belly, and a generation of demon kings appears in the world, stepping on the heaven and earth to determine the universe. I am respected from ancient times to this day." —— This book is also called "The Second Generation Demon King" and "My Brother is the Second Generation Demon King!" —— The author has something to say: There are some routines in the beginning, but the plot will start to be innovative later on. I hope you will support me. Later, different training systems will be developed from the perspective of the protagonist. In addition to traditional fantasy, some micro-innovations have also been made... [Introduction is weak, move to the main text]