Mitou Shoukan://Blood Sign

Mitou Shoukan://Blood Sign (未踏召喚://ブラッドサイン) is a light novel series by Kazuma Kamachi with illustrations by Waki Ikawa.

Plot
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!