Guys be ready, because Denjiro's character is on brink of being 'totally and utterly' destroyed just for sake of cheap cliffhanger.
Since his childhood Denjiro was quite smart and sneaky bastard, but he had to be, since he was an orphan. From his tough life Denjiro was forced to take responsibility from an early age and hence, developed a personality that allowed him to survive, he's a natural survivor💪. He knows how to fool and manipulate people, can easily spot a trick or trap, and is shown to be quite conscious to his approach. In terms of intellect
Denjiro is one the smartest characters in one piece, alongside characters like Ben Beckman, Vegapank, Akainu, Blackbeard, Sengoku the strategist etc. Denjiro single–handedly ensured the raid on Anigashima...
This man: managed to "single–handedly" infiltrate the enemy forces, build an army of loyal followers, collected information for 20 years, patiently served to a man that he wanted to kill for 20 years straight, raised and took care of his master's daughter, and finally but most importantly, he discovered the identity of the traitor and managed to save the entire raid, and he did it, all of that by himself. All other scabbards are absolutely useless compared to him.
Now, if by any chance, Denjiro falls for Kanjiro's trap and believes that that's the real Oden—whiteout asking any questions to him, like for example how did he survive... then Oda is going to destroy the best scabbard just for sake of cheap cliffhanger. On the other side, Kanjuro doing the same mistake by underestimating, Denjiro and the scabbards, would ruin his character. Oda has already done this type of things with Whitbeard and Sanji and I don't see a reason why he wouldn't do it with Denjiro.