The Unexplored Summon:// blood-sign (Volume)

is the first volume of the The Unexplored Summon:// blood-sign light novel series, written by Kazuma Kamachi and Illustrated by Waki Ikawa. It was released under the Dengeki Bunko Imprint in September 2014.

Synopsis
A summoning ritual to freely call even "those who were lurking deeper in the gods". Among the state-of-the-art summoners who handle it, there was a boy with the highest ability. "King of Immortality ", Kyousuke Shiroyama. The strongest boy summoner has only one fatal weakness. "Curse words" emitted from a girl. Help--. Kyousuke, who received the words of Meinogawa Higan, a girl standing on the edge of death, throws herself into the city where the three summoners collide! A new orthodox series of Kazuma Kamachi's whole body that is paired with "A Certain Magical Index" !!

(source: Bookwalker JP - Translated)