Slaadi are an alien race that dwells in the untended clutter of the Abyss. Able to make themselves look like anything they want (they're shapeshifters), they usually masquerade as whatever race they're dwelling with.
Morbatten, through the writings of Sage Alaura, recognizes levels of Slaadi as per the power ranking of dragons by color. That is, Green, Blue, Red, Gray, Black. Gray and black are distinctions the Slaadi themselves use and so Tania adopted that after Red.
The rest of this posting is about how Slaadi society works.
At Azuros +, Slaadi reproduce by creating transformant worms. Acting like parasites, these take control of a targeted host. Each worm contains a pearl of sentience from its maker. This enmeshes with the host giving the Slaad total access to their memories. Slaadi prepare targeted hosts by inscribing an Abyssal rune on their right shoulder. It looks like a spiral set of scars.
Once the worm takes root, the Maker can exert control and influence over the host. If they do not, within a few days, the worm will kill the host and be birthed as a Green/Fecudus slaad. They have 3 imperatives: please Master, acquire gold, and eat knowledge. Eating knowledge is key to progression as Greens cannot reproduce. At a certain point, they can buy their ascension with gold or they acquire the knowledge required to ascend to Azuros. Fecundus slaads have very weak access to Set's Dream, able to exert it as if gentle hypnosis... though it makes them very persuasive.
At Auzos level, the Slaad can now create transformant worms. This occurs only when they are sated on food. The ability to directly control other creatures through the worm and to move creatures into Set's Dream by touch brings the Slaad a new level of power. While faster consumption of knowledge, this is where the Slaad might learn magic, or seek out a profession. After all, knowing exactly how to forge a sword, is not the same actually being able to forge a sword... at least not one that would survive combat. With Set's Dream, paranoia and self-preservation instincts begin to kick in. At some point, the Azuros will consume a green (most often one they created) and their progression leap frogs. Want to know about how gold mining works? Infect a miner. Want to know how cook food? Infect a chef. The Azuros becomes much more targeted... and their paranoia shows them that they were probably created to be consumed by an Embros +. Very powerful Azuros will rarely join together to overthrow and share a meal of an Embros +.
At Embros, the Slaad can now infuse their identify into a worm. Upon infection, the new Slaad basically becomes a clone of the Embros + but at Green level. Embros can exert Set's Dream, with lasting effects, in line of sight. That is, a targeted creature might see themselves as a stronger servant of the Embros. They actually become stronger, even when the Embros is not around. This effect needs to be renewed around the cycles of the moon or it fades. Embros progress to Grey/Anthracos only by consuming an existing Anthracos.
Anthracos Slaads, because of cloning, are actually many. It's part of their instinct for self-preservation. Anthracos Slaads are able to generate Set's Dream in an area around them, which affects all creatures and matter in that space. It is, for all intents and purposes real. The older and more powerful the Anthracos, the larger the area affected. In Merakor's fall, it is said that a slaad blanketed the entire Arati Grasslands in Set's Dream... and that the effects still linger even though that slaad died shortly thereafter. A new imperative arises with Anthracos... awaken Set. They begin to notice that their access to the Dream strengthens after cataclysm and they become addicted to scheming to create bigger and bigger ones. They believe that Set will awaken with a big enough cataclysm. In addition to more powerful control over Set's Dream, Anthracos can create targeted worms that will arise at the any level below Embros.
Antramenti Slaads, or the black slaads. It is said there is only one, but the truth is far stranger. There are many... because the Anthracos feed on each other's clones who in turn have fed on the creations of other slaads. At the Antramenti level, near god-like in their power, Set's Dream can warp and bend reality... and the Antramenti use this power to create safehaven worlds far removed from other suspected Antramenti. The issue is that the paranoia is so strong and the consumed identities so many that each unique Antramenti knows virtually everything about all the others except for very small time lags, or through extreme scheming. Like assassins, they strike at the Anthacos hoping to fill gaps in the time lags between today and when the last other-Antramenti servant/clone was consumed. Like the Anthracos, they are addicted to cataclysm but so fear another gaining advantage with Set, that they spend most of their time blocking each other. Only when threat of death to a unique Antramenti becomes an issue do the Antramenti ever cooperate.
Because of this, Ylgolth exists as a collective of clones barely separated by feeding time from the Antrament'ylgolth. Here is another rendering of Ylgolth. Final note, their obsession with gold comes from the fact that gold does not lose its properties between planes.