The Great Debate
"The Great Debate" refers to a major disagreement in the interpretation of the Great Plan by the Slann of Lustria and the Southlands.
This is derived from my head canon and diverges sharply from published GW lore where the Lizardmen usually act as a unified bloc at all times.
The Great Debate centers around how the Slann and the First in general should shepherd and guide the other Forces of Order, namely the elves, dwarves, humans, ogres, and halflings. Sometimes these races are collectively called "the Prodigals", beings who have not betrayed the Old Ones outright but seem to have clearly lost their way.
To some extent the Great Debate has differing opinions on what to do about the mortal races that were not created according to the Old One's plan including, orcs, Goblins, Fimir, Skaven, Chimera among others. Generally speaking, creatures not meant to be according to the Great Plan are referred to as "Anathema" whether they are sapient like goblins or bestial like squigs.
The Great Debate also concerns those where are former members of the Forces of Order were corrupted by dark powers of some sort including but limited to the Warriors of Chaos, Dark Elves, Chaos Dwarves, and possibly the Vampire Counts and Tomb Kings. These groups are often collectively called the Fallen.
Many Slann (especially those in Mazdamundi's coalition) don't believe in differing between "Prodigals" and "Fallen" and just lump them altogether as the "Younger Races"
On the surface, it doesn't seem like that big deal. Big deal, politicians don't agree, this is normal.
This is normal for modern humans. Just like in Mandarin the written character for crisis and opportunity are very similar, in the Slann's language "argument' and "Chaos" are practically the same word.
Given that the Slann are all extremely powerful demigods, an argument that gets out of control can easily create cataclysmic supernatural disasters.
The Sides of the Debate
Generally Slann are either neutral or they are part of the Mazdamundi coalition or the Merestar coalition. That said, the coalitions are not 100% unified among themselves and they will often argue with each other over minor details. The main point of disagreement between the coalitions is where should the Younger Races should dwell.Mazdamundi's interpretation of the Great Plan
Mazdamundi believes that before the Great Catastrophe the elves all lived in Ulthuan, the dwarves all lived one particular mountain range, and the humans all lived in the Old World. There were no Anathema at all. The Old Ones set this as the default for the world, so the rest of the Great Plan cannot truly proceed at all until all the Younger Races move back to the lands they belong in and everyone else is destroyed. Madzamundi wants to move all elves, including Wood Elves and Dark Elves back to Ulthuan. He wants to move all humans back to the Old World, and all dwarves back to their original mountain range. Anyone that resists dies. Anything that didn't exist before the Great Cataclysm dies too.Merestar's interpretation of the Great Plan
Merestar believes that the younger races moving to new areas is not a deviation of the Great Plan, but the ultimate fulfilment of it. Every Daemon or Anathema slain by a elf, dwarf, human, ogre or halfling is an enemy that the First don't have to fight later. The First are coldblooded and cannot survive in some parts of the world easily, all the more reason to let the Prodigal races go to these places and secure them so the First don't have to. Merestar's has two prongs. The first prong is to eliminate all of the Fallen arguing that the Dark Elves constant attacks on Ulthuan are preventing the High Elves from reaching their full potential as Daemon killing warriors. Likewise, the Chaos Dwarves, undead, and Warriors of Chaos are holding the dwarves and humans back from their full potential The second prong is that the First should reach out to certain groups of Prodigals and make direct appeals for alliance so they can better coordinate actions against their mutual enemies. Merestar and his allies agree with Mazdamundi that the only good Anathema is a dead Anathema. The difference is Merestar does not believe all Anathema are equal. The Beastmen are the children of the Old Ones greatest foes, the Chaos gods. The Skaven are an immediate existential threat to the First. On a cosmic scale, the Orcs and Goblins are merely annoying. Once the Prodigal races are in a stronger position, Merestar believes the Anathema will be put on the defensive and they will quickly fall when all the Forces of Order are united against them.The Conflict
Prelude
The Great Cataclysm knocked the surviving Slann out of their collective complacency and made them all question their basic assumptions. Slann have been pondering and discussing "What to do about the younger races" almost from the moment these races were first spawned. Discussion increased around the Time of the Rat and Serpent which was also when Slann Lord Merestar created his own unauthorized experiment of Turochlitan
Battlefield
This is not a conventional battlefield. This is a battlefield of the mind, a war of ideas which is fitting because many Slann spend most of their lives living inside their own heads.
Conditions
The Slann wouldn't even dream of fighting each other directly. An actual drag out fight between Slann could literally destroy the world.
They haven't even considered letting their armies fight it out by proxy. None of the Slann want to needlessy deplete their armies on such an action.
The Engagement
Most of the conflict is being "fought" through telepathic debate.
Merestar's coalition is trying to win moral victories by sending minions out on quests to achieve small victories. Parts of Mazdamundi's coalition (without Mazdamundi's permission) have started trying to tie up Merestar's minions with the Lizardmen equivalent of red tape.
Slann don't always telepathically communicate in words. Sometimes they speak in images. It is concerned somewhat petty, but both sides will project mental re-plays of the other faction's failures at them periodically.
Belligerents
Strength
Mazdamundi, by his sheer prestige has won a lot of Slann to his position without half trying.
Not counting the many neutral or unaligned Slann, Mazdamundi's coalition makes up the majority of Slann in the Great Debate. Mazdamundi's allies are heavily concentrated in his own city of Hexoatl and the city of Itza. A fair number of Slann in Tlaxtlan.
Mazdamundi's support is limited outside the Big Four cities, with few Slann in the ruined Temple cities or Kahoun backing him. Mazdamundi has negligible supporters in the Southlands.
Merestar has converted the plurality of Slann in the kahouns and occupied ruins of Lustira. Because Merestar and his allies control the only means of telepathically contacting the Southlands Slann, Merestar was able to convert most of the Southland Slann to his vision.
Merestar has few supporters in the
"Big Four" Temple Cities.
Casualties
Objectives
Mazdamundi so far has opted not to act on his objectives directly, not yet. He wants to have more Slann working with him before he directs his forces outward to force his interpretation of the Great Plan on the world at large.
Mazdamundi and his allies have generally opted to not inform the Skinks under them about the Great Debate.
Merestar and his allies are not content merely to telepathically debate their ideas, they are attempting to live out their ideals. Or at least they are directing their Skink and Saurus leaders to live out their ideals.
Merestar and his allied Slann are hoping that if their minions make real gains in helping the Prodigal races and striking blows against the Fallen and Anathema, they can win converts to their cause by virtue of their success.
In order to accomplish this, the Slann in this coalition have informed many of their ranking Skink lieutenants of their grand designs.
Working from the title, I thought this was going to be a group of people sitting across from each other and voicing their thoughts. Since it's with telepathy, you could go more into depth with the mental strategies and tactics they used to broaden the analysis or interpretation of the consequences to each other.
That's a good idea. Both sides have have successes and failures, mostly failures. I can imagine telepaths using mental images of the other side failing to metaphorically rub the other side's face.