Rayllum and TDP

In some ways, the foundation is entirely laid as early as between 4x01—4x03, with the other 2/3rds of the season just occasionally reinforcing it. I say this for a couple of reasons. The first is that, by virtue of 4x01 being structured the way it is, Janai/Amaya's partnership is set in oppositional parallel to Callum/Rayla's: one couple is moving forwards and getting engaged, the other is stagnated and separated. 4x03 shows the shift in Ezran's perspective as he thinks about the future of his kingdom and the world, which is similarly reaffirmed by Janai a few episodes later:

Somehow, we have to hold it all in our hearts at the same time. We have to acknowledge the weight of the pain and loss, but open our eyes and allow ourselves to hope and maybe forgive and love again. We have to give today's children a chance to inherit a future filled with peace. To give them that, we have to hold pain and love in our hearts at the same time. (4x03)

KARIM: You and I... We won't live to see this new day. JANAI: No, we won't. But the future will be bright again. If not for you and I, then for our children, and their children, and their children. (4x06)

So we have a very strong sentiment of "we have to responsibly (and sustainably) build a future for future generations," both from a king and queen who will be routinely paralleled throughout the arc. It's a grand sentiment from Ezran, who is a child himself, and even at 20 would be a bit young to be having kids + doesn't have a canonical romantic partner. Janai, meanwhile, is set to marry Amaya, and could conceivably have children, representing many of the same things as Callum and Rayla's children would. They get the plot/socially relevant human-elf integration while Rayllum's in s4 is purely emotional, after all.

However, we also have 4x02, where Viren's speech lays it all out on the table.... and also points a flashing neon sign over Callum's head in particular, especially since their parallels as of 4x01 have been cranked up to 11.

My whole life, I've been chasing after things I didn't have. Influence. Status. Power. Now that I'm here, and I may have only 30 days left, do I really want to spend all those days chasing? Maybe I should stop... and appreciate what I do have, a-a month of life. Living each day to the fullest, watching beautiful sunsets together. Laughing, and enjoying every moment with my daughter, who is the most special person I have ever known.

And then we see this sentiment of "how could I put anything (glory, duty, power) over a simple life with / feeling connected to the people I love?" over. And over. And over again.

N'THAN: I'm supposed to catch my own dragon. It's what you have to do to grow up and become a real Drakerider. But... I just can't do it. (4x06)

REX IGNEOUS: Look around you. I sleep amongst piles of legendary treasures. Every finely crafted weapon loses its shine. Every relic's power goes dim. All things rust and rot around me! (4x08)

JANAI: What life do I want? There's only one thing I really know: Amaya, I want to marry you. I want a life with you. (4x08)

Here in the final gloaming of my days, I find what I most deeply desire is what I could have had all along: the love of my dear Conrad. The voices that called me away from him—duty, adventure, glory—are all hollow winds that have left me cold and dying alone. Conrad, if you were here, I would tell you I am sorry. Conrad, if you were here, I would tell you that the vast mystery I traveled the world to find was contained in you along. [...] Conrad, if you were here, I would tell you all my choices were nothing, and you are everything. (6x03)

AARAVOS: In all my many centuries and millennia, those few years with Leola were the most meaningful. Pondering the deepest mysteries of the universe could not hold a candle. (6x09)

CALLUM: One deep truth, huh? KOSMO: Your deepest truth. (6x06)

We know you're going to live an amazing, beautiful life. And where we're going, we'll have each other. We love you, Rayla. We always will. (6x09)

AARAVOS: To go on without her would mean an eternity of pain. But in that moment, I chose to live and my life took on new purpose. (6x09)

VIREN: Without magic, you're just a frail old man. You're a nobody. I am the High Mage of Katolis. I have purpose, power... and I intend to use them both. (6x06)

CALLUM: The right thing, I hope. I'm leaving with you. We'll do this together. [...] I'm sorry, Ezran. I can't be your High Mage anymore, but I'll always be your brother. (7x02)

MIYANA: I have nothing to my name, but I am safe. [...] My dreams have changed. I dream of a child who is healthy and happy, who plays and laughs, who is loved. Please, Karim. We tried to achieve so much, and we failed. But this... this dream, we can have. (7x05)

RUNAAN: I was trained to accept that I was already dead so that I might carry out my dark work without fear. But... I am not dead! I am alive! I have a family I love. I have so much to lose, the very things I took from you. (7x09)

And a refusal to engage with this viewpoint, in universe, typically (but not always) leads to nothing but more trouble and suffering. Karim and Claudia cannot, at least as of s7 and s4 (arguably s5) respectively, let go of their mission(s) and drive. They cannot let go of the ambitions they have, particularly for Karim, and it leads directly to his grisly, self-inflated end.

Now, I don't think TDP is arguing that getting married / having a partner and babies is the only meaningful life one can have. We actually have a good collection of characters who are canonically / perpetually single and perfectly happy (Opeli, Barius, Gren, Ezran as of S7) or who seek and find more fulfilment elsewhere (Lissa, Terry) after leaving their partners, or have to leave their family of origin (Soren). However, prioritizing genuine love, simplicity, and companionship over status, power, and control is a core theme of the series, as the former leads to connection and the latter often leads to dehumanization. Viren's attempts to lose nothing in pursuit of saving Soren's life leads him to magically murder Kpp'Ar and assault his wife, showing that while love was part of his motivation, it wasn't all of it; it got twisted.

The reason I say all this relates to Callum and Rayla most heavily as characters is [gestures to their character arcs] everything about them versus the royal characters in their lives.

Janai and Amaya have the option to leave and have that simple, peaceful life in Katolis in 4x08, so according to The Theme, shouldn't they take it? But Janai has grown into wanting to be queen, and have a positive impact (void of self-importance), so they stay. Ezran, too, loves his people, though his crown is a heavy burden. Lain and Tiadrin left Rayla with Runaan and Ethari, trading looking after one child for another out of duty.

The difference, here, is both motivation and priority. Lain and Tiadrin left to look after Zym because they believed it was in Rayla's best interest, and they took personal responsiblity for ensuring she grew up well cared for—and Ruthari / the Silvergrove aren't perfect by any means, but they do love Rayla, and she also knows that. (I also think it's very likely that Rayla will reexamine and reevaluate her parents' choices in arc 3 now that she's a parent herself, given that she still has to tackle her internalization of sacrifice leftover from S7.) Janai wants to be queen, and Amaya also knows that; moreover, she knows that both wants can be joined together, rather than having to choose and sacrifice one. Being king is difficult for Ezran, but also something he finds meaning and kinship through. It's not self-destructive the way that Rayla's fixation on duty or Callum's obsession with magic occasionally can be.

Furthermore, there's a reason when detailing the life he wants in 7x05, Callum doesn't mention politics or magic. Besides Rayla (and Ezran's) lives themselves, there is nothing he cares about more than the life he and Rayla could, or are, building together... and that inevitably involves children. Where Rayla's side of things will likely be focused on processing her previously unprocessed childhood trauma, and letting her character finally doing the 180 of prioritizing her loved ones and what she wants above duty, Callum gets the Viren-Aaravos parallels of "nothing is more important than my children, and I will sacrifice anything for them" (hi Callum destroying the primal stone in 1x09 for Zym, and probably handing over the Key of Aaravos for any version of Sarai II and/or Rayla combo in arc 3). Janai and Amaya don't have any of that, and never have. While they might have kids, and I expect Janai to free Kim'Dael to save her niblings in a parallel to Callum's arc, the groundwork isn't as layered and isn't as personal. But then again, Callum and Rayla are two main characters and the main ship of the show. As stated, the narrative forces have been on overdrive to the point while I wasn't sure they'd have a kid in arc 3 on account of "how're we gonna justify taking this baby into danger / our Y7 demographic's interest," I figured the desire for children and/or Rayla being pregnant was something the arc would literally HAVE to have just to make the entire rest of their characters kind of make sense, in terms of all the set up.

After all, the great Sin of the Cycle, on an Emotional Level, was the separation of parent from child. Of families. As one of my friends put it, this is the "sacrifice a child" show—Sarai II and the life with her parents, a life of peace, cannot be sacrificed in order for the narrative to come full circle for the show as a whole, but particularly for Callum and Rayla as individuals. Therefore, for their characters at this point in the story to function, she must exist to be their respective lynchpins and drive what arc 2 made a core theme to its final conclusion.