Mangekyou Sharingan Techniques.. Random, Biological, or Learn-able?

[Sephiron]

This is a really good theory, I would agree that it has to do with blood relations and I think it also has to do with how good there genjutsu, ninjutsu and/or taijutsu is when they're born.

Thanks, sorry fell asleep Zzz

And yes Itachi implanted Sasuke w/ a one-shot amaterasu; but not everyone believes that

OT: There seem to be a variety of connections that seem likely in it's own way.. including the randomness (...kinda)
I hope before the war is over Kishi verifies the connection between them, if there is one of course. Maybe the entire connection to Rinnegan as well

 

[-Hades-]

I think every MS has both basic jutsu like genjutsu and amaterasu and susanoo if you are skilled enough (or lucky enough or whatever) but besides that it has it's own unique thing...

Like Itachi has Tsukuiomi, Shishui had KA, Sasuke got blaze release, Kakashi and Obito have Kamui... we still don't know anything about Madara yet.

And i highly doubt you can train for these techniques, i mean i don't think Sasuke could get Kamui, nor did we see Madara use it, or Itachi who was a genius.... I mean how can you train for something like that, it's something your eyes do, they either can or can't do it... like a kkg for example, you can't train to get wood style.

 

[Sephiron]

I think every MS has both basic jutsu like genjutsu and amaterasu and susanoo if you are skilled enough (or lucky enough or whatever) but besides that it has it's own unique thing...

Like Itachi has Tsukuiomi, Shishui had KA, Sasuke got blaze release, Kakashi and Obito have Kamui... we still don't know anything about Madara yet.

And i highly doubt you can train for these techniques, i mean i don't think Sasuke could get Kamui, nor did we see Madara use it, or Itachi who was a genius.... I mean how can you train for something like that, it's something your eyes do, they either can or can't do it... like a kkg for example, you can't train to get wood style.

Well based on Itachi and Shisui who were highly skilled in genjustu and desired to be influential change the world, considering both of them I believe saw the pain and destruction that war brings- their MS abilities relate to influencing and enemy either through torture/ violent methods (Itachi-Tsu) or Peaceful yet deceiving (Shisui-KA), which some may call special or random, however in Sasuke and Obito's case their MS gave them abilities they desired greatly in such a time of need.

Elaborating further, When obito was crushed by the rocks he was said to have useda technqiue so some rocks went through him (Kamui )to benefit his survival stated by Madara after he was discovered, although it cost him more than a huge chunk of his body. Also when Sasuke really desired to help Karin.. desperate not to lose another comrade when he was having Team 7 nostalgia he focused on the Amaterasu which had set her ablaze, in hopes of stopping the flames.. which it did.

For all of the said Uchiha mentioned (no Madara) it was instinctual, and based from their view of the situations and overall ideology. And possibly changes/ Awakens whether they're more focused with a situation at hand (like Sasuke or Obito), or long term world changing goals (like Itachi and Shisui).

 

[Mitarashi]

I think it depends on the reason why they activated the MS.
Or what age, or skill level at the time.