The eternals are – according to mythology – a group of people cursed with eternity by Darzuh, one of the five Dragon emperors.
As the story goes, there was once an extremely powerfull mage in the service of Darzuh. After years of seemingly loyal service, she began to develop her own agenda. She devised a powerfull spell that could have killed not only her master, but would unravel the free will of any mortal. The dragon emperor caught on to her and cursed her and her twenty servants. This curse made them unable to die and gave them superiour regeneration. Then the dragon emperor went on to play with them as he saw fit. Pulling them apart and watching them regenerate on a dailly basis among many other unspeakable things. After the dragon emperors dissappeared, they became free and wandered the world, their minds tainted by their acts of treachery and infidelity.
In the campaign
Deep in the lair of the serpent cult, our heroic skyknights found a manuscript describing possible ways to permanently put an Eternal down.
Unknown to the party, they already met two eternals.