uzumaki connection with seals and with senju kinjuts with orochimaru sharingan obses
if most seals have an uzumaki seal, why would they need it,well you don't need that trade mark instead you can make your own seal with codes.think about it orochimaru seal it has a different code than uzumaki trademark like the curse seal
he took power from an original user like jugo
and put his power in a seal the curse mark.
the seals are usually to seal people,internal genjutsu,object, etc
but you must make your own code and this takes great effort
plus it depends on how you make it and how much the seal can take because apparently seals have limits like everything else depending on how much the user put in the seal= like how the death god has a limit.
notice doesn't the curse mark seal look odd from minato seal it's because orochimaru read his books and was able to put jugo power in a seal and stabilize= this would explain failed creation of the curse mark seal beside those orochimaru four ninja and sasuke since they got the good dose.
basically error in the code will give failed results and not all the power the seal can give you and major side effects like orochimaru patients
since the uzumaki were known world wide not nation wide it would explain why other ninja in nation and over the world would use an uzumaki trademark summoning the most.
apparently the uzumaki were great at these codes somehow idk maybe because there related to the sage
uzumaki created these codes but even those codes they created would have side effects like giving the user death like death god
it usually takes power from one,chakra, objects
so orochimaru tech like his five element seal has the same rules just override that seal but even orochimaru has some diffulculty on this because of it's complex code but showed some good progress onmaking seals
you guys hav to understand that you can just make a seal on like that it takes time possibly years of the exxperiments you go threw.
if it was that easy you will see more ninja with space time ninjutsu
honestly orochimaru could be a relative to the sage of six path it not far fetched all sage relative do far fected things like eating tailed beast,having dojutsu,
i think that the senju when they were married to the uzumaki were able to upgrade their jutsu like to moves like kinjutsu= like summoning world iimpure ressurection also naruto shadow clones that is not normal just to let you know it's kinjutsu
if you notice the uzumaki we've seen have anourmas chakra or special chakra
which is best for there kininjutsu and also the senju have chakra that is strong to like orochimaru
basically the kinjutsu was made by senju but is an upgraded version from the uzumaki fuinninjutsu because of the senju and uzmaki uniting so they will share there tech this is how kinjutsu is made this is not easy you can read all the books but you need to master them so you can do it correctly like using a sharingan to be able to copy things like fake notes of perfect things and to write down codes perfectly
the sharingan is perfect for copying codes tobi might have actually took a fuinijutsu scroll or kinjutsu scroll/codes to do his space time tech
basically the senju mixed the funijutsu with summoning to make kinjutsu
all kinjutsu is from the senju clan
most fuininjutsu is from uzumaki
and orochimaru would want a sharingan for it's abilties so he can master all the jutsu
so he can make a code like funinjutsu and kinjutus,plus to make space time
tobi not using a sharingan nowhere does it stae that he only dissapeares in a swirl leaving his eye as the last thing there he could of designed it like that and put a special seal to his eye= tobi is a scientsit to it wouldn't be hard for him plus with code knowledge he could copy space time ninjutsu and alter the codes making it better than predesscer's like tobirama