Are you referring to the yin/yang seals that Hagoromo gave Naruto and Sasuke?
no, not only that but the whole duality theme/symbol is ever present on everything in the last story arc of Shippuden. This is even driven home to the fact that Momoshiki and Kinshiki (along side Urashiki before he was axed). Which means the Otsutsuki race travel in pairs.
Also the fact that they were born twins and the whole Inda vs Asura, main family vs branch family, etc.
Yes, Yin and Yang symbolism also applies to Hagoromo and Hamura.
The seals I believe are to make them have each other's powers.
Based on parallels, we can assume that Hagoromo is the older and talented one as well as being the Yin.
This is mainly due to the fact that he has the Rinnegan and Sage Mode and is dark in complexion (characteristics of Yin). The only thing that isn't Yin about him is his masculinity. That is very Yang. Vice versa for Hamura (younger, possibly hard working instead of talented, light complexion)
Perhaps they were much like Naruto and Sasuke. They didn't have the full use of the 6 Paths and so they gave each other their chakra (similar to Obito giving Kakashi his Sharingan and Orochimaru giving Sage Mode to Sasuke through the Curse Mark).
I think the rinnesharingan represents yin and yang. I cant say much else about it right now.
That is true in a sense before The Last movie and the introduction of Hamura and the Tenseigan in general.
I believe that the Rinnegan is more (Yin-Yin+Yang) while the Tenseigan/Chakra Mode is more (Yang - Yin+Yang).
This is even further backed by the fact of the duality theme and pairing of the Otsutsuki aliens.
My guess is its a seal for a transformation.
Yeah but you'd think that since he is Yin, he'd be more mind focused than heart/body focused. Perhaps it is because he probably had a chakra fruit before as well (although that wouldn't make sense since Momoshiki is Yin and he unlocked the 3rd eye)
Transformation wouldn't be too farfetched but it is certainly unique. We did see Momoshiki transform too but that would mean that Isshiki already ate a chakra fruit then.
Maybe its a rinnesharingan tech is what I meant to say. An ability of the chakra fruit. I feel there is an element of genetic engineering involved with the karma seal. Perhaps it has something to do with the creation of a ten tails? Or the evolution of one.
Well, everything is derivative of the Rinnesharingan as it is the transcendence of every being. (basically if you're Yin, you get Yang and vice versa).
I don't understand why you think Hagoromo is yin but he is known as the Sage of Six Paths
The theme of duality. Also Hamura is a Sage of 6 Paths as well. It isn't strictly Hagoromo. Hagoromo is merely the Earth's Sage of 6 Paths and Hamura is the Moon's.
We also know that Momoshiki was using Petra path on Killer Bee and Naruto. Meaning that Momoshiki is a Path user, if not being considered a Sage himself. As to whether or not he is a So6P is questionable until he ate Kinshiki.
I'd say that pre-chakra fruit, both Momoshiki and Kinshiki were like Sasuke and Naruto. Only able to use 3 Paths max. Although we only ever saw the Petra Path being used (which is why I made a theory of the 6 Otsutsuki aliens each being a Sage of 1 Path). Then Kaguya transcended and became a Sage of 6 Paths. Then had twins where they were 3 Paths users (like Naruto and Sasuke) but put on the seals of the other to use other 3 paths that they each had making them both Sages of 6 Paths.
The byakugan unlocking a chakra mode is possible based on what we learned from Toneri
Byakugan? Or did you mean Tenseigan?
Regardless of which one, the fact that the Chakra Mode is linked to Hamura points more towards the Uzumaki and Toneri's branch family being one and the same.
Although, not quite sure how it is relevant to the topic?
As for Hamura being Yang, parallels.
yin = dark = doujutsu = talented = mature = spiritual = imagination = mind
yang = light = latent = hard working = late bloomer = physical = tangible = body
As Indra had the Mangekyu, he made ninjutsu (imagination brought to reality)
He is the older sibling, he matured faster and is more talented.
Asura had to build himself up and wait to mature and in turn had to rely on ninshu (linking himself with other people)
Hamura is on the same boat as he did not have Tenseigan until later. That is my basis on Hamura being the Yang. Also he is light AF compared to Hagoromo's darker complexion.