Big Order Vol. 5 (manga)

Sena has summoned "God," and it's slowly breaking through the gate to the human realm! With the entire world on the brink of collapse, Eiji finally swears to kill his sister and end the calamity. But he's going to need help, and that's exactly what he gets when he and Rin are reunited with two comrades who claim to know how to defeat Sena's unholy monstrosity! Even so, will Eiji really be able to end the life of the sister he has spent so long protecting? It's a fight for the future, and only one sibling will prevail in this breathtaking finale!