Seal

From Wiki Resolution

The Dragons of Heaven (天の龍, Ten No Ryū), or The Seven Seals (七の封印, Nanatsu No Fūin), are a group of seven individuals per city who are fated to stand against the Dragons of Earth in the apocalyptic battle on the Promised Day to determine the fate of the Earth and humanity.

The Dragons of Heaven ideologically represent the belief that conflicts between man and nature can and must be resolved peaceably, and that humanity is no less precious than the Earth itself. They each exhibit the ability to create kekkai (barrier fields) in order to prevent innocent people from being harmed when battle with the Dragons of Earth erupts. It is heavily suggested that when a Dragon of Heaven loses the person or people that they wish to protect, or loses the will to protect others, the Dragon of Heaven concurrently loses their ability to create kekkai and is no longer considered as a Dragon of Heaven.

The sigil of the Dragons of Heaven is the constellation of the seven stars of the Big Dipper.