manhwa mc with dark power

Chen Beiming, a young member of the Star Alliance, was assassinated under the order of the Five Emperors. Unexpectedly, his soul went back to the past of 10 years ago, granting him the chance to change his destiny, as well as to take his revenge on those who was behind his death.

When Su Xiaobai is dying from an illness, he accidentally comes to another world with the remaining soul of Long Ming, Star King, the strongest human in this world, in his body. He gains the strongest ability called "Infinity of Darkness" at the price of feeling terrible pain whenever he gets an erection. Only when he finds out the person who plotted Long Ming's death and succeeds to the throne can the pain disappear...

In her past life, Su Yaoguang bought Xiao Yanci, supported his education, and helped him rise to great heights. She became his wife. Everyone praised him for never abandoning the farm girl who funded his rise. Su Yaoguang also believed she had found a good man. Unexpectedly, when she was seriously ill, she saw Xiao Yanci bring his first love and a child who resembled them both to her bedside. "Dad, mom, when will this person die?" the child asked, holding Xiao Yanci's hand. Xiao Yanci responded, "Soon, just wait a bit longer." That was the moment she realized: she had wasted her entire life on the wrong man. Returning to the age of fifteen, Su Yaoguang pointed at the bloody young boy: "I want him." In her past life, no matter what she gave Xiao Yanci, she only received a cold expression. This time, the young boy, like a wolf cub, dropped his guard; everything Sister gifted was the best. Sweet as milk. Devoted beyond reason. He melted her completely. Until one day, the young boy took a high position. Not wanting history to repeat itself, Su Yaoguang packed her things and slipped away at night, only to run into a man as noble and unattainable as a deity. "I've heard you call us siblings everywhere. Good sister, shouldn't we change what we call each other?"