So the Back bone begining of the story is.

Mindscape Irida
(Simple Explanation)

Mindscape Exists Inside a Dimension called Nullsphere which resides outside the Omniverse unbounded by Time and its Logic.

This place was simply created through the thoughts and emotions or smart life (Mostly Humans).

The first ever being to exist within the Confines of Nullsphere’s is known as “Legend” and he was the creator of the Light Realm (Mindscape) and created the first ever Angels who were his Offspring.

Eventually due to jealousy and rivalry one of the Angels was Banished from the Light Realm. This created discord among the groups of Angels. Some remained loyal and some rebelled.

Eventually the rebelling angels combined their power to forge a weapon that could Kill Legend and they could take his power for their own Greed.

This worked as the loyal angels and Legend fought against the rebellion and lost miserably. They ate Legend to conserve his Power but that didn’t work instead they Petrified his Heart creating the “Irida Prism” (Although their greedy asses can barely do stuff with it)

Through many years the Angels Reproduced with their brothers and sisters created lesser beings known as the Proteus. Later the Slants… and the lowest ones.

“Ovals”

They Created the City of Carcossa where they resided as their overlords and lesser species would worship them and Gods. (many of these Angels are Cannibals by the way)

Their Species were forced to a caste System.
Proteus would serve in the Armada and would get the most pay and most luxury in their lives as also lesser Rulers.

Slants would do most of the holy work and would live decently but nothing like the Proteus.

Ovals… no one cares about them. They are mostly served as a delicacy and they live in the outskirts of the City.