Prove me wrong.

Both are voiced by Takahiro Sakurai.

Both are eccentric and are very skilled at removing or killing ‘oddities’ in one way or another. If you think about it, thats all Mononoke are – oddities.

Their personalities are extremely similar too, they both are calm and cool-headed most of the time and simply do what they need to do, but also seem to have an air of cockiness, especially when doing their ‘job’.

Not only that but the way they get rid of the oddities is very similar too. Learn the truth, regret, and form, then you know your target and can fight it. Neither of these guys does anything before knowing that information. Take the first arc in Bakemonogatari, Meme doesn’t do shit until forcing staple-bitch to give him the full story – then still did nothing until she explained how she regretted losing her family bonds – and the form was already known in the first place. After that he’s able to, along with her, ‘beat’ the oddity. The medicine seller works the exact same way, and in his case he CAN’T even do anything about it until he knows those three things even if he wants to speed things up, I’m sure it’s like that for both of them though.

They even ‘look’ the same in a way. Obviously not literally, but their eccentricities show in their looks in both shows – and if it werent for the difference in time period they’d look the same probably.

Same person.