Six Great Gods

Background
According to Ainz's speculations the Six Gods are most likely players from YGGDRASIL. They appeared before the rule of the Eight Greed Kings and might be one of first visitors from YGGDRASIL. While they may no longer exist in the present day, their legacy still exists through the Slane Theocracy and their descendants, who are regarded as demi-gods in the New World, one of them is Zesshi Zetsumei (絶死絶命).

Trivia

 * Ranked Magic was introduced to the New World by them, which resulted in the corrosion of Wild Magic.