Weapon Ascension Material.
Lighting a lamp could dispel darkness, so the people of the borderland believed that as long as the lamps of the Lightkeepers were alight, the home of the living would be free of vile spirits.
The warriors who had sworn to watch over the night believed the same. That is why, like moths to a flame, the man faced a mountain of evil with his fragile flesh clad in armor.
Until the black tide consumes his flesh, or his flesh devours the black tide, when the two cannot be differentiated from one another.