Tang San's Twin Sister - Chapter 145

Summoning ceremonies can freely call forth even “those which lurk in the depths beyond the gods”. One boy has top-level abilities even among the cutting-edge summoners who can use those ceremonies. He is Alice (with) Rabbit aka Shiroyama Kyousuke. But this strongest boy summoner has a single fatal weakness. Certain “cursed words” spoken by girls: “Help me.”

When Kyousuke hears those words from Meinokawa Higan, a girl brought to the verge of death, he throws himself into a city where three great summoner forces clash!

For the once dead Hua Yu Man, she has to do three things this lifetime: kill those who harmed her, kill the man who said he loved her, and protect a place called “home.”

She seems docile and gentle, with the air and temperament of a beautiful young lady. But in fact her heart is cold, overbearing, and black belly, with a mysterious identity that can drive the world crazy.

He is the Thirteenth Prince, but also the country’s disgrace; a cold and ruthless man who doesn’t put human lives in his eyes. But only towards a sometimes gentle, sometimes willful and sometimes disobedient woman, would this man be ceaselessly doting and spoiling.

- Description from Novelupdates

King Grey has unrivaled strength, wealth, and prestige in a world governed by martial ability. However, solitude lingers closely behind those with great power. Beneath the glamorous exterior of a powerful king lurks the shell of man, devoid of purpose and will. 

Reincarnated into a new world filled with magic and monsters, the king has a second chance to relive his life. Correcting the mistakes of his past will not be his only challenge, however. Underneath the peace and prosperity of the new world is an undercurrent threatening to destroy everything he has worked for, questioning his role and reason for being born again.