The Aspect Lords are an infinite amount of sets of an infinite amount of omnipotent^infinity and omniscient^infinity beings created by The True God or more powerful aspect lords who are aware of their parallel existences in alternate versions of many regions of The Box and work together with each other to form somewhat of a government throughout The Box.
More generally, the term "Aspect Lord" can also be used to refer to any omnipotent1 or greater entity that is not connected to altarca cosmologies. In this sense, Aspect Lords may not cooperate, as the sheer scale and capability of the Box allows entities to disagree in this way.
The Aspect Lords use their omniscience to work in unison with each other, so they automatically know the solution to everything, and everything that potentially will and can happen.
Of course, for any set of Aspect Lords cooperating with one another, there is a different set with the opposite objectives, and an infinite volume of the Box that none of them are able to affect. Some of them exist separate from the others, some meet in altarcae, and others still follow laws of existence or nonexistence that simple mortals are unable to grasp.
When an aspect lord is destroyed, usually by other aspect lords, their remains, if any, form a material known as Xaspunum, which is the most powerful material in existence.