MTL - The Dreamer in the Spring Boudoir - Chapter 41 Hidden disaster

Rainer, an amateur arcanist and college student, sought to create a new spell far surpassing the magic of the few he inherited from his grandfather. Yet the interference of an unknown event during the casting of his spell led him to be thrown through space and time.

Being given a chance and reincarnated is nice and all, yet why do I have to become that male friend who just watches the protagonist flirting with his harem?---World: Kaguya-sama: Love Is War - Hyouka ----

Xu Ping'an was overjoyed to marry, but what welcomed him was a deception.Eight years of devotion, eight years of infatuation, only to be repaid by the one he loved plucking his spine and devouring his bloodline.“You take my spine, I'll turn my Thunder Sword into bone, defy the heavens to change my fate, and awaken the memories of the Immortal Emperor from a past life.”In this life, I will make all those who betrayed me descend into Hell!

I finally managed to kill the demon lord.