Intro

So I've been reading The Lion: Son of the Forest and while I've been a fan of 40k for over a decade now (since Space Marine 1), I really haven't delved into the lore on a micro level (characters rather than events or tales). So, I'm sure I'm not the first to say this stuff, but I don't have a lot of people irl who would care enough about 40k to be interested in hearing it. So, apologies if this is all repeats of what's been said before.

The Statesman

Not even getting into their personalities (which I am weakest in my knowledge of), they are a perfect contrasting, yet complimentary, pairing of rulers.

In one half of the galaxy you have most emperor-like (lower case 'e') Roboute Guilliman, the Statesman, who sees a state fallen to decay and starts about fixing it's systems, instituting reforms, and reclaiming lost lands.

Roboute even gets the Emperor's sword, symbolizing his new nature as a Roman emperor-styled conqueror. Despite not being that great of a fighter compared to his brothers and now even less so being partially disabled encased in life-support armor that heavily hinders the dexterity needed to be a skillful swordsmen. If the Emperor was Caesar (the great leader who was killed by traitors before he could accomplish his goals) then Roboute is perhaps Augustus (the one who can reform and hold the civilization together, conquer territories, and lead the nation back to greatness).

The King

In the other half, Lion El' Jonson, the King, sees his people cut off, victimized, and even his own sons are killing each other over past sins (real or perceived). So, he goes about saving his people, slaying mighty foes, levying troops, and redeeming his lost sons.

The Lion most obviously mirrors King Arthur and the Green Knight. Who focuses more on questing and relationships than strictly governing. In fact it could be that the relationships and questing is what builds a nation willing to follow their king in the first place. And despite being one of the best fighters among the Primarchs he is not given the sword but the shield of the Emperor. This time he's not just a conqueror, but first and foremost a protector.

Two Sides of a Coin

The Statesman's primary concern is saving the state, the King's primary concern is saving his people. Two sides of the same coin of good and competent leaders who seek to save their civilization. Both sides are distinct yet needed. A perfect pairing.

To my limited knowledge on their personalities both have changed a LOT since TGC & HH.

Guilliman has lost most if not all of his optimism and hope, yet has arguably accomplished more against greater odds since his awakening than he did before. And for the first time in 10k years humanity is actually starting to pay off its deficit and fight against it's slow decline (still not in the black yet, but it's better than just making things worse). Despite Guilliman losing hope, he has brought hope back to humanity.

The Lion used to see everything in black and white, friend or foe, his paranoia led him to take rash extreme measures (Calth), and his pride made him unable to admit fault or correct his path. But age and time have shaved away many callouses. He goes about treating common man with respect and care, he redeems the Fallen, and even when he learns, from Dante, that the one loyalist brother of his to return was the one he fought with the most he says this:

>Roboute.
I am not alone.

In Closing

As I said earlier, I'm more new to this side of the lore and I haven't finished the book yet, or looked up what these two do upon seeing each other face-to-face again. Perhaps it's because I'm a Salamanders and Raptors fan, I love good will and pragmatism, but I am tired of the infinite dark age, incompetent government, and perpetual hopeless grim dark. Will humanity win? Probably not, but it's nice to have even a sliver of hope. After all, without hope they've already lost.

Who's Next?

Who do you think would make a good returning Primarch (loyalist or traitor)? Is it just one of them or multiple? How would it push the story forward besides just another cool character coming back? How do you think they've changed?

My guesses:
The Poet & The Orator
I think Corvus and Lorgar returning would be awesome! Lorgar converting whole worlds to chaos, and Corvus hunting him down in a cat and mouse murder game. Perhaps the catalyst for their return is Sicarus being destroyed somehow (perhaps by Corvus or a ritual by Lorgar).

The Rook & The Knight
Dorn and Khan. The Castle Lord and the Mongol Raider. Khan comes out of the webway with the technology needed to complete it for the Imperium. Thus increasing travel speeds and being much safer and reliable than warp drive (just gotta worry about Dark Eldar and maybe a laughing god), this expands humanity's maneuverability to reconquer the galaxy and respond to threats, as well as slightly lessens the power of the Warp by not needing to interact with it all the time (affects on the Golden Throne???). Dorn fortifies and holds the territories under threat (similar to England's burhs), as well as guards the webway gates from those without proper visas.

Maybe Kahn got to the Black Library or was tortured by Dark Eldar (if they're even that fast) and comes back with new knowledge beyond webway tech or is changed somehow. Dorn comes back... single handedly... (I don't know much about him tbh). Honestly, I don't think my idea for this is great, but someone who is actually good at this could make these two work as good returns.

The ones who might be too boring

Russ and Vulkan. I'm saying this and the Salamanders are my favorite chapter, I don't see how they massively change things things and push the story forward other than being two cool characters who return just because the band is getting back together again. I mean Russ could go hunt Magnus and other traitors, maybe he or Vulkan found a way to perma kill them. The most compelling story arch (that I don't think is even possible afaik) is maybe they are able to redeem Fulgrim and/or Mortarion. Which would be insane! It would take a miracle greater than even the apotheosis of Saint Celestine for it to even have a slimmer of a chance of working.

The Redeemer & The Sinner
If Russ redeems Fulgrim. Russ being a savior from sin rather than an executioner of sinners, and not totally hating psykers, would be a big character shift.

The Revived & The Reviler
If Vulkan saves Mortarion. The Emperor's message to Mortarion actually sounded a little sad and loving, Vulkan is the embodiment of the Emperor's love. Love is probably the only thing that could save one as far gone, morbid, and regretful as Mortarion, who is a traitor but never wanted to become what he is now, plus he didn't like just being a tool, he wanted to be a son, but with the Emperor's changes he may be able to see the Emperor as a heavenly father figure not just another warlord (similar to Christians and their God, but through veneration not worship).
Redemption arcs can be really good (if they make more sense than pro-wrestling turn-face/heel) but it's so bright and hopeful in a grimdark universe that I feel it would only come as either a prelude to ultimate triumph or as a last burst of hope before ultimate defeat, at least in Warhammer.

The Meme

The 2nd and 11th Legion Primarchs are revealed, but it's actually Alpharius who is playing both roles, who is actually Omegon playing all three roles.