There are many mysteries still surrounding these weapons, examples are;
- How Itachi got them
- Can it block a TBB
- The effects of a kg or tota on it, particularly dust release
- Effects of kamui on it since the db has basically described this match as a immovable object vs unstoppable force scenario
- Can the sword seal a tailed beast
However this thread isn't about these issues because they would still remain unknown. Neither weapons were truly tested to its limits to give an accurate answer. This thread however is to state that neither weapon has a fixed size and the size of the weapon fluctuates depending on who wields it.
Before i go onto the my main reasons, just by looking at the weapons and comparing their size to naruto,bee and itachi its at least 20 times bigger than them. I find it very hard to believe that the weapons magically fitted susano to wield. Almost as if they were tailor-made for something as big as susano to wield. Not when the manga has made clear that its a weapon that orochimaru has sorted for some time, but also it doesnt come with susano. No human could wield a weapon 20 times as big as them, its impossible so who was the weapon created for. Definitely not a human, a giant perhaps? :confused:
We know that both weapons have some transformation ability. The totsuka is from a gourd and the sword itself is liquid. The yata mirror changes its properties in accordance with the attack;
However what governs both these transformation abilities is that, both weapons are ethereal weapons or in other words spiritual weapons with no physical form.
From the description its very possible that because it has no physical form but also has other transformation abilities its very possible that its size fluctuates depending on the wielder, therefore if an entity smaller than susano was to try and wield it, it could possible decrease in size to allow this. Similarly if an entity bigger than susano was to wield it, lets say a perfect susano, it would increase in size to allow this. The weapons are very similar to susano itself because that is also an ethereal weapon. Its size changes in accordance with what the user wants, these are the stages of susano.