Seems like you might need a little hand there. First of all i support the fact that everything said about the legendary weapons are hyperboles and this isn't the first time that kishi has exaggerated. Also state that itachi isn't invincible as there is no such thing in naruto. However this hyperbole which relates to the weapons to an extent are viable simple because there are not normal weapons.
We have seen hyperboles gives to other weapons like the 7 swordsmen weapons. True these weapons are special but its fair to say, compared to a weapon with a tag 'legendary' they pail in comparison. Its never stated that these weapons belong to rikudou sennin like the other weapons we have seen that has been attributed to him and i don't believe there are his weapons because his weapons have a unique and set look about them. The weapons itachi wields are too different and unique to compare with rikudou's. What im trying to say is that i believe there are other special people in naruto that might rival rikuodu or might be slightly less power than him and its them who's wielded these weapons.
Anway ive already created a thread about size maniuplation here [
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]. Yes i believe either swords can be wielded with human hands. However you talk of shape manipulation, something i could've talked about however i didn't but its possible. First is that the weapons are ethereal, meaning they have no set form. Having no set form means that it can change size and possible shape, but also it cane become tangible (blocked hydrao's head, kusanai sword and bombs) but also remain intangible.
We have seen various other weapons which has shown both size and shape manipulation. First is enma when it transform's into Kongonyoi. In this form it has shown both shape and size manipulation. Size manipulation [
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]. Its length can not only increase but enma can manifest parts of its body. It has shown as shape manipulation here [
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].
Peopl here do not know this but the Totsuka sword is not a counter to oro's sword of kusanagi but rather its a variate of it. Now people do not know that oro's kusanagi sword has shown us both shape and size manipulation. Example the sword can turn into a snake and go back to oro, this is shape manipulation [
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]. Similar it has shown us size manipulation [
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]
So we have seen enma show shape and size manipulation but also oro's kusunagi sword demonstrate a similar feat.
Every stated from the db portrays either of itachi's weapons to be able to do something similar and infact they have. Owarij has covered some points and the link i uploaded also covered some points. However ill cut more specific pages from the manga.
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So yes everything supports tangibility and intangibility but also size and possible shape manipulation.
However i believe it does more than that. People usually only ninjutsu based attack though the db entry and even manga scans disagree. I believe it does more, i believe one of the abilities it can do is use the opponent's attack against them therefore its void. People usually state well if an opponent uses fire, it will change to water and i agree with this. However i believe it could do more and again ill upload a previous post.
Do you think orochimaru who lust for power will not spend his time and by time there is an emphasis of searched for all his life [
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]. If oro is searching for something he believes it will make hims tronger. If oro is searching for something for something his WHOLE LIFE he believes it would ridiculously make him stronger. The hype of the weapons are is not only because it has the tag legendary, but also because oro was looking for them