I don't really believe Daruk and Urbosa were...

[xMasterShakex]

From everything we've seen in Breath of the Wild's universe so far, I'm still not convinced that Daruk and Urbosa were really the grandparents of Yunobo and Riju. Especially with Urbosa. It just seems so messed up that she had a kid in Botw yet never mentioned her anywhere, especially with what we know about Urbosa's extreme loving and maternal instincts. Urbosa says in her own diary:
"Emissaries from Hyrule came to see me today. They informed me that I have been chosen to pilot the Divine Beast.
My people are uneasy about it. They tell me such a dangerous task is not fitting for the chief. I understand their fear.
However, I intend to accept this task."

Nothing about her daughter, eh?
And why would Urbosa be the sitting monarch of the Gerudo if she already had an heir to take over? The only reason I can think of is that Urbosa's daughter was too young, which makes the idea of Urbosa even having a child in Botw's story all the more worse. There's far more evidence in her character against it, especially given how intensely devoted she is to Zelda. Her last words when she gets KO'd in Age of Calamity is her telling her "little bird" she's sorry.

Daruk and Yunobo seem more closely related but I think it's mostly because of their shared bloodline power as opposed to Urbosa and Riju's lightning power being divine right. Urbosa says in the Aoc mission "Wisdom of the Storm" that Yunobo is "cut from good granite, just like Daruk". This sounds more like they simply share a common Goron ancestor than Yunobo being the grandson of Daruk.
What's also weird is that Yunobo never once calls Daruk his "grandfather" or "grandpa", or vice versa with Daruk ever calling Yunobo his "grandson" or "grandchild". It's always "ancestor" or "descendant", which Nintendo shamefully misuses in the game when referring to Sidon and Teba as part of the Champion "descendant" unit (LOL, wtf?).
Daruk always came off as more like the great uncle of Yunobo even when I first played Botw. So ****ed up too that he never mentioned he had a son. I really don't believe he did. He's got a stronger bond with his little "bro" Link than this supposed son of his. The only excuse I can think of for his missing child is that he must've ****ed a woman and got her pregnant before he died. Not very responsible, mature, and gold-hearted behavior from the Great Daruk, is it, given everything we know about the Goron Champion's character?
I really don't believe any of the Champions had kids, including Daruk and Urbosa. Of course I do think they share recent common ancestors with Yunobo and Riju, but I don't really believe they're the respective grandparents of those two. There's far more evidence that they're simply relatives who share blood by recent common descent.

 

[Chevywolf30]

We also don't know how reproduction works with the Gerudo and Gorons, especially the Gorons.

 

[Link&Midna]

We also don't know how reproduction works with the Gerudo and Gorons, especially the Gorons.

they reproduce with each other ofc, thats why gorons are allowed into gerudo town

 

[Uwu_Oocoo2]

Well in the zelda Canon "descendant" doesn't always necessarily mean by blood. For example, Makar from ww is said to be a descendant of a certain Kokiri whose name I can't recall. Considering the Kokiri are all children, for him to have descendant is... concerning, to say the least. There may be something similar going on in botw. For the Gorons it could be explained with "urm rock people reproduce differently ig idk". As for the gerudo, Riju could be a descendant in the fact that she eventually claimed the throne, but not by blood. Lighting powers could conceivably come with the thunder helm, it's hard to say.

 

[xMasterShakex]

The reason I said Urbosa probably had a daughter and Daruk probably had a son is because we've only ever seen female Gerudo and male Gorons (with the exception of Gerudo King Ganon, of course), so I'm assuming that's what they had. But whatever the sex of their supposed children, it's still messed up they were never mentioned. I remain unconvinced, and believe that Riju and Yunobo were simply close relatives of Urbosa and Daruk, not grandchildren.

 

[GZ Zelda]

Kind of a necro, but I don't actually think Riju was ever described as Urbosa's descendant. I'm pretty sure whatever chief took over after Urbosa (not her daughter) is the lineage that Riju is a part of (considering you would think Riju would inherit Urbosa's Fury, and yet the only lightning powers we see her use comes from the prayer involved with the Thunder Helm).

As for Daruk, we don't know how Gorons reproduce. I would assume asexually, so it's possible that Daruk's son was simply "budding," in a dormant state during the events of 100 years ago. Or Daruk just left him at home as we never see any memories taking place in Goron City. This "asexual reproduction" doesn't really explain how a bloodline could be passed in a way where Yunobo has Daruk's powers, but idk.

 

[Moblinking5000]

As for Daruk, we don't know how Gorons reproduce. I would assume asexually, so it's possible that Daruk's son was simply "budding," in a dormant state during the events of 100 years ago. Or Daruk just left him at home as we never see any memories taking place in Goron City. This "asexual reproduction" doesn't really explain how a bloodline could be passed in a way where Yunobo has Daruk's powers, but idk.

Considering the fact that they're sexless despite the fact that their gender is male, you may have a point. It's also interesting to note that they are sexless, as the Gerudo allow them into Gerudo Town. This gives me an idea for a theory...

 

[Spiritual Mask Salesman]

I don't remember Riju being confirmed to have any direct relation to Urbosa besides the fact that Urbosa was the Gerudo Chieftian 100 years ago. The Thunderhelm is said to be a "family heirloom", but if Urbosa did not have a child before her death than a new line of royality would have had to step in.

If Gerudo have about the same lifespan as Hylians than that'd put Urbosa in her 40's or 50's maybe. If she had a daughter than she'd probably already be an adult by the time of the Calamity. Regardless, it's still weird that Urbosa never mentions having a daughter.