The Omni Lords

The Great 8 is a group of powerful ancient monsters known as Omni Lords, who have sealed a great evil beast known as Yamigedo. They consist of monsters from multiple worlds. Most of them claim to have no recollection of these events. 7 out of 8 Omni Lords have been revealed.

Biography
Thousands of years ago, a coalition of eight monsters, each hailing from a different world, combined their powers to seal away Yamigedo on Earth, so as to stop the creature from devouring more worlds. Now that Yamigedo has been unsealed, they must gather again to prevent the beast from devouring Earth and to the other worlds. However, over the years, some of the members have lost their memories for various reasons, which they need to regain to seal him away, and some may even be unaware they are an Omni Lord or might keep it a secret like Asmodai does. Like Ziun, most Omni Lords have lied dormant. Others such as Asmodai and Count Dawn are aware of their status as Omni Lords but keep it a secret.

Indentification
There are 2 forms of identitification to discern whether a being is an Omni Lord or not.

1st method: The number of "horns" they have

As stated by Count Dawn, each Omni Lord has a number of "horns" around their face/head equal to that Omni Lord's number/position within the group. Take note that facial hair and armor decorations can also count as "horns" and it does not have to be part of their body to count as a horn.

This identification method can result in mistaking others as Omni Lords, one example being Akatsuki mistaking a Rhinoceros for being the First Omni Beast Lord due the singular horn it has. This was disproven by Zanya stating that the species of that Rhinocerous is known to only have 1 horn.
 * Ziun: 1 - 1 prominent horn
 * Asmodai: 2 - 2 horns, one on each side of his head
 * Tenbu: 5 - 1 horn on his snout, 2 horns, one on each side of his head and 2 antler-like horns.
 * Variable Cord: 6 - 6 golden horns, 3 each on each side of its head.
 * Dawn: 7 - 4 hair points, 2 for each end of his mustache and 1 for his goatee

2nd Method: The Omni Lord Emblem

Each Omni Lord carries a colored orb Core Gadget which is refered to as the Omni Lord Emblem. Each Omni Lord carries said orb close by and should 2 Emblems come into close contact with another, the orbs will react, proving and confirming the other wielder as a legitimate Omni Lord.

The Omni Lord Emblems seem to be the key to an Omni Lord's status as when Tenbu was about to die, he passed on the title of Omni Lord and his Emblem to Drum before being devoured by Yamigedo.

Members

 * First Omni Beast Lord, Ziun - Katana World
 * Second Omni Demon Lord, Asmodai - Magic World
 * Third Omni Water Lord, Miseria - Dungeon World
 * Fourth Omni Fire Lord, Burn Nova - Ancient World
 * Fifth Omni Dragon Lord, Tenbu - Dragon World (deceased)
 * Fifth Omni Dragon Lord, Drum - Dragon World (successor)
 * Sixth Omni Storm Lord, Variable Cord - Star Dragon World
 * Seventh Omni Earth Lord, Count Dawn - Legend World
 * Eighth Omni Deity Lord, ??? - Possibly Darkness Dragon World or Danger World