3-POSSIBILITY N.3 – KANJURO
This one is extremely likely. We need to remember; Kanjuro’s actual drawings are not only godlike, but they can talk and move as well – Kanjuro drew himself jumping on a boat with the Scabbards and having a long conversation with them, even resisting the rainwater. Also, Kanjuro is the only person who could pull off a realistic Oden not only in physical appearance, but in character as well, as he’s both a perfect actor and he’s been with Oden for a long time.
It would also make sense for the swords; Kanjuro knows that Zoro has Enma and that Ame No Habakiri is in Tenguyama’s possession, so his Oden doesn’t have them. This could also explain Bao Huang’s silence about him; Kanjuro was never an enemy to begin with, and they don’t know he was defeated by the Scabbards. Also, we don’t know the range at which Kanjuro can activate his drawings, making it possible Oden was created just a few feet away from the Scabbards.
However, there are issues with this reasoning, the main one being: why? The thing is: Kanjuro didn’t need to draw Oden if he wanted to lure the Scabbards out, they were coming out on their own – and I doubt Kanjuro wouldn’t have known this, especially since he’s so big in people profiling and could have predicted their mindset; and if Kanjuro had a change of heart, then… why? Again, Kanjuro would know the Scabbards, and making an Oden drawing is just cruel, as they didn’t need Oden to get a morale boost – they were coming out to fight either way.
So which one is it? Is Kanjuro just toying with them and trying to kill their morale, so that Jack can deliver a more devastating blow? Is he that hellbent on revenge? Or is Kanjuro now working with them after Orochi’s “death”, and in that case why use Oden? The final possibility is that Kanjuro knows Orochi is still alive, and this is a plan the both of them have come up with in order to get rid of them on their own. But I seriously doubt that Kanjuro and Orochi would even move a finger, considering they could just watch the war and its conclusion and then act upon it. Maybe killing the scabbards now is the best chance they have. But it still doesn’t make too much sense.
4-POSSIBILITY N.4 – ONIMARU
This is the other most likely answer, but this comes with A LOT of caveats. First let’s examine why this would make sense. First of all, Onimaru is a kitsune, a mythical creature that can – in theory – shapeshift. According to the mythos, turning into Oden would not be outside of the realm of possibilities.
Onimaru could also just slip through Bao Huang undetected pretty easily, as he would just have to remain in fox form until reaching the Scabbards. It would also make sense on a narrative level, if we take into consideration the good possibility that Hiyori was the one who saved the Scabbards, as he would have been the only other person left on mainland Wano who could have come to Onigashima with her – both were at Ringo the last time we saw them.
However, there are also a series of negatives to this theory; first, we’re taking this into consideration thinking Onimaru is an actual mythical creature who can shapeshift into anybody. For now, the only ACTUAL mythical creature we’ve ever seen in the series is… well, the artificial Dragons made by Vegapunk and the one from Wano legends – who, for all we know, could have been a Devil Fruit user. There’s a lot we still don’t know about Onimaru, namely how could he ever turn into Gyukimaru.
My main hypothesis on this is that Onimaru ate a Devil Fruit of the Ito-Ito no Mi – Monk Model variety or something; I say this because Onimaru never transformed into a human form while he was with Kawamatsu, and that would have been much more suited for transporting weapons and whatnot. But even if we consider the possibility that Onimaru is a mythical creature, then we know that he gives his human forms specific traits – the eyes are the same, same goes for the eyebrows and the whiskers. But now that he turns into Oden he can hide them? But even this is just a speculation on his abilities.
The other big question mark is: why? Just like we said with Kanjuro, the Scabbards didn’t need someone to tell them to fight, they were going to anyway. And turning into Oden would just be too cruel for them, and it would literally kill their morale as soon as this would be found out. So… why?