- Doing It for the Art: The series' summoning system is mind-bogglingly complicated, with more rules than can be fit into any one volume, and an entire menagerie of original and bizarre monsters. In the afterword of the first volume, Kamachi mentions writing a dictionary that included all of the terminology used in the series.
- No Export for You: So far this series has not been officially published in English.
- What Could Have Been: A lot of titles were proposed for the series, before settling on the current one. Some examples include "White Queen and Blood Sign", "Alice (with) Rabbit - Unkilling King" and "Concerning the Matter of my Former Girlfriend being the Last Boss".
- The Wiki Rule: Here.
Trivia / The Unexplored Summon://Blood-Sign