The Zelin Clan was a large clan within the demon race; they were the most numerous in terms of quantity, and according to the investigations conducted by the Temple Alliance, the Zelin Clan’s total population was at least 3 millions. About 100,000 Dual Bladed Demons from the Zelin Clan would perish on the battlefield every year.

The Zelin Clan’s Dual Bladed Demons were the most commonly seen demons. They were not a mutation of humans, but a mutation of a kind of magical beast among the ones that became mutated at the moment the 72 Demon Gods descended. 

Normal Dual Bladed Demons from the Zelin Clan were black-colored, their whole body covered by a carapace, and describing them from the human standards, it could be said that they had only external spiritual energy and no internal spiritual energy, a demon specie that relied on their physical strength for close ranged combat. 

However, when a black-colored Dual Bladed Demon from the Zelin Clan turned dark-green, it meant that they went through an evolution. In that case, they became equivalent to Kings within the Zelin Clan.