There doesn't have to be one. When you use Cop, do
have
to include a Godfather AND a Miller? The answer you don't have to include both or either even. But Godfather is explicitly a Non-Normal role anyway.
Now Mafia Doctor to the Gunsmith is what GF is to Cop, except it's a Normal Role. There are multiple "Millers" to the Gunsmith. Any variant of Cop, plus Vig and other GSs will return "have a gun". In thruth only the Vig is a killing role even, but that's the way the Gunsmith works.
So, a Gunsmith could exist without any role that gives them a fake result, but then that would be effectively a Cop. "Has a Gun" = Guilty and "Doesn't have a Gun" = Innocent. So, WHY use a Gunsmith instead of a Cop in the first place is the question. The answer is either there is a Mafia Doctor or there is a Vig.. or both.
Seph claimed Vig alright, but regardless of whether I chose to belive him or not that does not explain why Mafia decided it was a good idea to leave me alive AND not block me. If Mafia do NOT have a RB, and they don't have a Doctor either, then I'm either going to get a guilty on one of them or I'm going to clear a Townie.
So, them not shooting me is confirmation enough they have a "Miller" to my role, which is the Doctor.
Now who was I expected to check? Mew was. Why? Because -they thought- I'd want to verify whether he was Ascetic or not, and -according to their plan- I should have got a result on him, and -if he was Town- the result would have been "Does not have a Gun". Right?
Now my problem is why would Mafia want me to confirm Mew as a Townie?? The answer is the result is fake because he is a Mafia Doctor. He even got upset I checked someone else because my check on Koki defied their plan. Instead of clearing the Mafia Doctor I went on to confirm a suspected Town slot that would have been very much lynchable otherwise (courtesy of the fake mason claim with Joey).
The plan was for me to confirm Mew, and they would lynch in PP/Koki (Mew also put you and Oka in his lynch pool). Then I get shot to confirm my role and alignment to Town, so Mew becomes even more confirmed to you (because you would know I was telling the truth).
Another mislynch on the other one from PP/Koki and a successful NK on you/Oka/Dva = a 3 v 2 LyLo with Gamma very much lynchable (they probably would've kept Oka alive because he would lynch both PP and Gamma).
Now reread for more comprehension. The starting point is "Why would Mafia keep a claimed Town Gumsmith alive?", and you can work it out yourself from that point.
once yu get to Mew is 100% a Mafia Doctor; you will have another question: So who has blocked A50 on N1 then? If DrD was a Goon (flipped) and Mew is the Mafia Doctor, then the third one is the Roleblocker.
Note: There is NO Jailkeeper on the Scum side, because you don't put a Doctor AND a Jailkeeper on the same team. Not even on the Town side.
Seph can prove he's a Vig by shooting Gamma tonight. If you see only one death tomorrow and that is Me/Koki/Oka/Nako/DVa then you know Seph is lying, because as a Vig his shooting pool is limited to Gamma/PP at this point.
On short, there has to be 2 NKs tonight if we're going to buy Seph's claim to begin with, but if Mafia want to frame him then they'd have to no kill, thus leaving the Towniest players alive.
Again, assuming Seph is Town, and he goes for the Gamma shot (Sorry, Gamma, but Oka won't stop suspecting you, so you eat a bullet for "the greater good"
) and Scum will have to NO KILL or Seph will be CONFIRMED.