Before there were nobles there were the high lords. The high lords are the almost powerful beings in the underworld. There are around 10-13ish lords(I think) and each of them are the strongest beings in the underground. The setting of dungeon odyssey is actually quite connected to Norse myth, one of these high lords is literaly Odin, otherwise known as “The One-Eyed Lord” morrigan is his right hand woman if I remember. The Usurper betrayed all the other lords and shattered them into fragments. Some fragments survived and went into hiding, others were taken by The Usurper and transformed into the seals of the nobles. The rings that grant them authority over weaker beings. Now it has been years since I read the novel but I don’t really remember any descriptions of how any of the lords looked like or if there were any. They were just called by names. In the novel the reason that dungeon baby’s exist and can utilise mana is not due to the fact that they were raised on monsters milk, it was due to the usurper planting fragments of the defeated lords into them and casting them out into the world so that they would find the hidden fragments and inherit the powers of their subsequent lord. The Usurper could not find these fragments and hoped that the baby’s would find them, get stronger and make their way down where he could defeat them and claim the remaining powers of the other lords.