Like the tag implies, spoilers for ALL Mistborn books. Also, this is just a rambling write up of some thoughts I had.
I'm re listening to the original Mistborn trilogy, and I'm in the middle of WoA. There's the conversation between Dockson and Vin, and Vin sees the pain and guilt in his eyes. She uses that as proof that he wasn't the Kandra.
It got me thinking, and I realized that we never get any confirmation if that was reasonable. That if he *was* the Kandra, if he would he able to replicate that genuine emotion and connection. I know we're *told* that they can, or at least implied that they can, but do we ever see it?
I kept thinking about Kandra and I've realized that as an audience, we never truly experience the what the characters basically explain as the typical Kandra plot. By that, I mean that a character that we know and trust, one that we have a history with, is taken, tortured, and replaced by a Kandra as a spy.
To prove my point, I'm going to go through the main Kandra impersonations we see and determine if they really fit the bill.
Here's what I define as the Complete Kandra Experience^tm as set up by the books:
The audience has met the character to be replaced *before* they are replaced.
Both the audience and a POV character has experience and connection with the character before they are replaced.
The character goes through the Kandra process of being stalked, interrogated, and consumed.
The Kandra, while disguised as the character, replicates the emotions and connections that character would have.
The Kandra is revealed and the audience and characters are both shocked and grieved for the fate of the replaced character.
So the first person we know to be replaced by a Kandra is Lord Renoux, by OreSeur. We never knew Renoux before he was OreSeur. We don't meet any characters that knew Renoux before he was OreSeur. In a way, it's kind of a shallow replacement because Renoux doesn't seem to have anyone close to him that OreSeur has to trick. At least that we see. Obviously he was stalked and tortured and eaten, but other than that, he doesn't fit.
Then we have OreSeur as Kelsier. This one doesn't fit because 1. We don't see OreSeur acting like Kelsier and 2. He doesn't have to trick any of Kelsier's close friends. And the typical wine and dine approach doesn't apply because Kelsier told OreSeur to do it.
Now we come to the main Kandra scheme in the first Era: TenSoon as OreSeur. Technically we knew OreSeur before this happens. But he's being Renoux for most of it and emotionlessly following orders the rest. We don't get *any* emotional connection with who OreSeur is. And TenSoon doesn't really *need* to act like OreSeur and honestly he's kind of bad at it. He's far more proactive in helping Vin than OreSeur ever was. That's okay though, because neither we or Vin actually know OreSeur that well. And while we're devestated by the reveal, we're not really hurt by the fact by that OreSeur is gone.
Then into Hero of Ages, the only person that gets imitated is a brief stint of TenSoon as Kelsier, but that's no mystery.
We only get a couple of true imitations in Era 2. Most of the time the Kandra are being themselves, a vague persona, or a background character.
The biggest is obviously Bleeder/Lessie/Innate/Pa'alm, who I will henceforth be referring to as BLIP. This is actually the closest thing we get to my criteria, at least on an emotional level. *We* don't know Innate before he's replaced, but Wax seems to. It seems that Innate went through the Kandra process before he was replaced. And we do think we get to know him, even if he sucks a little. The biggest thing that BLIP shows genuine emotion and connection as Innate, especially when their bodyguard dies. The problem becomes that much of that emotion is BLIP's own and unfortunately, she's not exactly stable. And since we never knew the real Innate, we don't know if he'd react the same.
Then there's MeLaan's short stint as Innate, but there's nothing too emotionally deep about that.
TLDR, we actually never experience the Kandra as presented: immaculate mimics that will flawlessly take the place of close friends and family, including simulating their emotional depth and connection. We practically never know the characters they replace beforehand and we never see them actually replicate the deep emotions and connections of that character. That isn't necessarily a bad thing, but I thought it was interesting.