Ladder of Heaven

Ladder of Heaven (天の梯子 Ten no Hashigo) is a weapon stipulated as the strongest and evilest.

Description
Although the Ladder of Heaven remains a mystery, it has been revealed that the reconstruction during the ten years after the war mankind speaks proudly about is nothing more than a mere weapon specialized for massacre. Ladder of Heaven, given the name of the strongest and evilest weapon, is what connects heaven and earth. Born from the Great Gastrea War, it is a super weapon that saw the defeat of humanity.