Legendary Summoners!

Summoners. They have the power to summon all kinds of creatures. From the weakest to the strongest. In the Continent of Heresia, summoners are a very noble and mighty occupation there is. But, a summoner will never be a true summoner without their book. This book is very different from normal books. It's called, Grimoire.

A grimoire can only be called a terrifying weapon in the hands of summoners. This is their main weapon. Although, it's very nice to be a summoner and have a grimoire. Becoming one can only be based on your potential and also. Luck.

Also, there are 7 terrifying and legendary Grimoire in the Continent of Heresia. Seven Grimoires, accompaning Seven Sins.

Grimoire of Pride
Grimoire of Wrath
Grimoire of Gluttony
Grimoire of Lust
Grimoire of Sloth
Grimoire of Greed
Grimoire of Envy

Seven sins, seven legendary grimoires, and seven powerful summoners. What will happen if all seven appear in one era?