[Theory] Hagoromo is all seeing.

[Senju Bean]

Hagoromo is all seeing.

How the heck can he see what is going on across dimensions?

Spoiler

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Naruto can't even sense someone in another dimension, even with Rikudo Senjutsu.

 

[slayerdanger]

Hagoromo is the strongest, and most versatile behind Kaguya.

 

[dark legion]

because the marks on his hands appeared , was a signal that the seal was done . he didn't see it , he understood what they did , by his hands !

 

[Tarinth]

because the marks on his hands appeared , was a signal that the seal was done . he didn't see it , he understood what they did , by his hands !

Exactly this. I thought the panel made it rather clear actually considering Hagoromo
was staring at his hands when he said it.