I'm The King of Business & Technology in the Modern World - Chapter 12: Celebration of Victory

[Urban Martial Arts, Passionate Martial World.] He was a super expert who, due to accepting an inheritance, underwent a physical transformation that put his life at risk. To extend his life, the king returned...

[Mature Content]I was born a bastard to the Archduke of Beloria, scorned because of my odd-looking hair and sickly body, maltreated by my stepmother and sister.And my father? He never looked my way. I was the reminder of a mistake he could never accept.My entire life should've been trying to live through my days as a labeled whores daughter and the taint to the noble house but everything changed when my marriage to the Lycan Monarch was announced.Lycans are apex predators, superior beings, beastmen, and originators of those horror stories your parents told you about to make you behave. My father saw fit to throw me to the beasts as a means to reclaim the lost lands.I was the bargain for a better future for the last human kingdom, but I felt more cursed than blessed. Forced into training to please a beast and ensure I was fit to be his wife.I dreaded the day I'd wed the Monarch and be treated no less than human meat. I've heard stories about him, and they are far worse than any combined. They call him a mindless beast, merciless, the ultimate feared being in the entire realm, and the terror that bested the vampires in war and ended it under his rule.My future was bleak.But when the day arrived and I set my gaze on the beast I'm meant to marry... I realized Drevon Balthar was unlike the rumors; they didn't tell the whole story.

While the demons were rising, mankind was about to become extinct. Six temples rose and protected the last territory of mankind.

A young boy joins the temple as a knight to save his mother. During his journey full of miracles and tricks in the world where temples and demons are antagonistic to each other, will he be able to ascend to the strongest knight and inherit the sealed divine throne?

- Description from novelupdates

Shaymon, the man who has achieved the apex of dark magic, is framed as being a Demon King and is killed.