Protagonist, antagonist... Was he really one of the two ? I'm starting to think very strange thoughts with all the reading I've been doing in the last three-four days. This isn't to improve my case.
Like Comatose, I think Rashek wanted to set things right at the beginning. His people should have been dominant since the prophecy (the real one, the one that was counterfeited) had been given to them. I understand his point of view. So he was instructed by Kwaan to kill Alendi if he just could not loose him in the Terris mountains. Let's believe that TLR is Rashek. It is obvious to me that the well spirit work had started corrupting the prophecy way before the advent of Alendi. It takes time for all feruchemists to empty their metal mind and refil them by reading what they wrote again. If there was only one, it could have been fast but they were not bred yet. So it took time before Alendi, and yet once Alendi was found, it kept on changing things, subtly.
It is possible that Rashek suffered from this. Imagine one moment, the ones leading your people being fool by a spirit of some sort, being defeated by what they considered most sacred : their feruchemy. Of course Kwaan would have been persecuted for his belief. He might also have died defending it. It seems to me that Terris people are sincere and honest and don't easily bend. They must have been hard on him. Rashek might have had some resentment toward them. The official story is that Rashek killed Alendi so let's stick to it (for my own sanity).
Rashek kills Alendi in the Terris mountains and then goes himself to the Well of Ascension. Somehow, I do not think it was instilled by Kwaan. He doesn't mention that on his metal work. But maybe Rashek thought that HE was the Hero. After all, who could that be now that Alendi was dead ? The Šeepness was there, making everyone desperate. So, he takes it upon himself to go to the well. Now, before I continue, I cannot recall a single place where it says that Rashek was feruchemist. Don't jump ! But I only have a small reluctance on this even after all the threads I've read. Whatever he was before, it got changed afterwards. Comatose, you might say that you don't believe that TLR is using hemalurgy, but I tend to believe it when I read it in Brandon's annotations. He would not lie, would he ? Would he lead us astray voluntarily ? Unless the well spirit is active in this world, I don't think so. So here Rashek to the Well of Ascension investigated with POWER so immense ! He's got the power to change the world, to set it right. He sees the Deepness and does something. Now the more I think of it, the less I think that the Deepness was the regular mist or even the Mist Spirit.
Like Kwaan suggest, it might be the Well that created the Deepness just to force people to act. So here, Rashek acted but not the way it was hoping. When I read Vin's thought when the POWER invests her, I see one thing. Vin is in love and what pushed her to act is love, at that moment, she is no more the paranoid kid. Things she wants to do are things that love is pleased in, things that are agreable. When Rashek was in the same situation, he was already bitter. For all that we know, Alendi could have been the first man he killed and eventhough he did not like him, he might have come to realize as Kwaan did that the man was a good man. So he might have felt guilty also. And angry towards his fellow Terrisman, worst even toward the feruchemists that forced him to do what he did. It might be also that they killed his uncle, his woman and what not. Now if the POWER intensified Vin's feeling what do you think Rashek's feeling would have been intensified like ? Let's say, it's just a huge rioting they both received from the Well in addition to the POWER. But let's say that the Well spirit is not quite finished.
The Well spirit talks to Vin to convince her to give up the POWER so it could be freed. I have no doubt whatsoever that this spirit talked to Rashek as well. Once Vin liberated the POWER, it doesn't talk to her anymore, but Rashek did not do this... Do you see where this leads ? And how is a man suppose to react to such pressure after 5 years ? 10 ? 276 ? 589 ? 1000 ? His feelings only gets worst of course, the rioting constant. He wants to destroy the Terris Nation, but he still loves them somewhere. If he destroys feruchemy, the tool of the well spirit, his people (or what's left of them) can go on living. So he starts breeding the feruchemy out in the hope to salvage what's left. We have no reason to believe that Rashek did not love his people. He had the highest hopes for them ! The inner room was placated with reminders of his former life. He must have been desperate to see them survive. If only the feruchemy could be bred out ! Understand he only wanted to erase lies...
But the well spirit is not happy. Inquisitors is its counter balance. The Well spirit might be giving power to TLR, but it is also its torn in the flesh, his weakness. Whatever we think we know, it is what the Inquisitors and the Obligators taught the people, not reality for sure. They manipulated the truth just like the Well Spirit did. Like father like son. Did TLR really created the Inquisitors or the Well Spirit in him ? They were certainly meant to destroy, right from the beginning of their creation. I suggest that the Inquisitor were a tool of the Well spirit and therefore keep a hand on the control of its creation. The Well Spirit still talks to Zane telling him to kill everyone but Vin. It needs her to release it. It talks to Marsh to kill Sazed to stop him from reaching Vin. If Marsh cant help it after just a few weeks or months... how do you want TLR to manage so long without any effect ?
I tell you, TLR is a victim...