How come not all subjects of Ymir have royal (Fritz) blood?

Question

All of today's Eldians have a common ancestor, Ymir. But in all Eldians there is also a royal bloodline, Fritz/Reiss. This royal bloodline came from King Fritz. As far as we know, King Fritz and Ymir have three daughters. Thus, should not all Eldians be also descendent of King Fritz? This only makes sense if Ymir had kids with someone else, other than King Fritz, but that is not shown. What am I missing? Or is it a plot-hole?

To rephrase it.
We know Ymir only obeys commands of the royal family and that's why the Founding Titan can only be used by those of the royal family. But, if all Eldians are her descendants, and she only had children with the royal King Fritz, all Eldians should be Fritz. But, that is not the case. Why?

Answer 1

All Subjects of Ymir are Eldians, but not all Eldians are Subjects of Ymir or Royal.

Technically, every subject of Ymir has Royal blood, but it is not enough to make an impact. Remember, King Fritz was just a human and his bloodline can be diluted to the point where Ymir does not recognize it and all subjects are connected through Paths so that can not be diluted. Only one of the 3 daughters was kept as the Queen of Eldia and kept the Royal Family bloodline as pure as possible (possibly through incest, IDK. Historia was not a result of incest so it is a bit confusing). The other 2 were used as breeding machines to create more subjects of Ymir, diluting the Royal blood immensely.

Answer 2

I'm going to go with the original poster and claim this as a plot hole.

Every Subject of Ymir should be able to trace their lineage directly back to Ymir and the first King Fritz. Incest isn't mentioned and Fritz's last wish for his daughters was to reproduce as much as possible to pass down the Titan's power. This would mean the daughters would need to take "lowborn" husbands to pass on the bloodline. Again, incest isn't mentioned, so Fritz's grandchildren would also take commoners as mates (male or female), so forth, and so on with every generation. With Fritz and Ymir as the progenitors for ALL subjects of Ymir and excluding incest (since it isn't mentioned), I can't think of a way for the royal bloodline to be so indistinguishable enough for the Founding Titan's power to be passed down only through a specific lineage.

For all intents and purposes, every Ymir Subject is as much of a cousin to the next and any Ymir Subject should (theoretically) be able to use the Founding Titan's power. Unless it's passed down through the male lineage, but Fritz didn't have any sons. Unless it's passed through the female lineage, but what would make a daughter from Sheena more apt to the Founding Titan's powers than a daughter from Maria, since they are both direct descendants from Ymir/Fritz? Unless it's passed down through the Fritz's ruling line of succession, but that's just through a naming convention to where, if that were the case, then the FT's power simply follows a named successor (and that's just silly).

Hmm, my last point may very well be the case of how the bloodline remains "distinctly Fritz" - in name only, I guess.

Answer 3

Remember that Ymir/Founding Titan can change whatever they want with Ymir's Subject that includes everyone, and since one of them is the successor to the queen, then King Fritz can just make Ymir do it and change whatever it is on their body.

It's on season 4 where they discuss there was a plague and then Ymir changed the insides of Eldians and since then, everyone is immune to it, like the queen can literally make her newborns an animal or a superhuman and she may even be possible to her newborn to a titan without using spinal fluids.

Maybe that's why there are 7 titans? Maybe that's why some Founding Titan may have to make a little more but scared of a betrayal like she made those Colossal Titans for the wall. Maybe, a long time ago, there were more titans (maybe, just maybe, that could have happened) and maybe those 7 are the only survivors of the great titan war.

Answer 4

I'm going to refer back to my answer here.

The original Ymir exists inside of the Coordinate as a thinking entity. She is the one who is the gatekeeper to who is allowed to use the power of the Founding Titan. Due to her time as a slave and all the trauma she suffered in life, she was very loyal to King Fritz and did whatever he told her to do. This loyalty can be thought of as mental conditioning, brainwashing, or a fear of disobeying, but whatever the case, it was shown as a fact in the episode From You, 2000 Years Ago that she obeyed Fritz unconditionally.

This "loyalty" continued even after Ymir died and she was reduced to whatever she is inside the Coordinate. According to the wiki at least, it does indeed seem to be stated somewhere that everyone who can turn into a Titan is descended from Ymir. So, what's the distinction between those of royal blood and the regular Subjects of Ymir? We don't actually have to understand the distinction. All we have to know is that Ymir knows the difference. Perhaps the distinction is even nonsensical, but so long as Ymir believes there is a distinction, she will use it to decide whether to obey or not. She exists as a thinking entity, after all, and with her mind as broken as it is, it makes sense that it wouldn't make sense. Once you put a person in charge of deciding these things, rather than a force of nature which cannot err, all bets are off.

And this is just speculation now, but perhaps, as with the vow to renounce war, the choice for Ymir only to obey members of a certain lineage was something imposed on her some point after King Fritz. Or perhaps it was a sanity check for Ymir, because with so many descendants, she'd almost have to give precedence to some (though this particular theory might not hold much credence, given how time works vastly differently inside the Coordinate). There's been some suggestion that inbreeding of the royals may also have kept the royals more genetically similar to Ymir, which could be the case. Whatever the case, if the explanation makes sense to you, it might make sense to Ymir, and Ymir's the one deciding, so...

Getting back to my original theory, what exactly is the proof that Ymir is the one deciding who is royal and who isn't? It's the fact that she's able to change the rules!

In the same episode, Eren Yeager is able to gain control of the Founding Titan. Sure, he has to play by the rules to get to the Coordinate and get an audience with Ymir, mainly by going through Zeke who has royal blood, but once there, he's actually able to convince Ymir to let him use the power. I forget exactly what Eren said to convince her (might check later and update this), but essentially he appeals to Ymir's desire to stop being a slave.

Answer 5

This question has been bugging me for weeks now.

And I am convinced that I found the answer. So, Maria, Rose and Sheena were pushed to reproduce to save the "powers" of Ymir right?

But there were only 9 Titan Powers.

So let's say each of them had 5 babies. That's 15 descendants of Ymir. But not all of them will be considered royal blood. I think only those who inherited the 9 titan powers will be dubbed to be royal at the time. Considering how Ymir the slave only became royal after gaining the titan powers.