Though Christian imagery often permeates the pages of fantasy and science novels, it generally falls into one of two categories:
1) The C.S. Lewis Category: Aslan is great; He's so awesome; everything about Him is cool, cool, cool. I really love Aslan.
2) The Philip Pullman Category: The Church sucks, it's really horrible; everything about it blows, blows, blows. I really hate the Church.
Some might say such a tactic is dangerous for a Christian writer. The god/emperor of the Final Empire is cruel and vindictive and could, upon first reading, seem almost to represent the cruel and vindictive God of the Old Testament. This quickly proves to not be so, however; though there are three separate story lines throughout the novel (Vin, Kelsier, and the unnamed Hero of Ages), much of the more blatant Christian imagery revolves specifically around Kelsior, the "Survivor" of the Pits who presents the common people of the Final Empire, the skaa, with a new god to worship.
Be that as it may, however, it is the journal entries that provide the chapter "bumps" which provides the most food for thought. They are ostensibly written by the Lord Ruler when he was young, before he became an emperor/god and was known instead as the Hero of Ages. It is the Hero of Ages who is to save mankind and he often parallels Christ in many ways, as this prophecy (which could be applied to either the Hero or Christ) clearly shows: "The Hero of Ages shall not be a man, but a force. No nation may claim him, no woman shall keep him, and no king may slay him. He shall belong to none, not even himself." (page 342) In addition, both men come from humble beginnings, rural towns and modest families: "I think it would do men well to remember that this task was not begun by emperors, priests, prophets, or generals. [...] It began in a small, unimportant town whose name would mean nothing to you. It began with a youth, the son of a blacksmith [...]. It began with me." (page 266) Finally, if these allusions to Christ are not enough, the prophecies say that, "He will be their savior, yet they shall call him heretic." (page 146) There is little doubt that the Hero of Ages is a Christ figure.
What is interesting, then, is the manner in which the unnamed Hero of Ages presents himself in the journal entries--while the philosophers of his time name him the savior of the world, he is dubious as to the veracity of their claims. The Prologue to the book opens with this introduction:
Sometimes I worry that I'm not the hero everyone thinks I am.
The philosophers assure me that this is the time, that the signs have been met. But I still wonder if they have the wrong man. So many people depend on me. They say I will hold the future of the entire world on my arms.
What would they think if they knew that their champion--the Hero of Ages, their savior--doubted himself? Perhaps they wouldn't be shocked at all. In a way, this is what worries me most. Maybe, in their hearts, they wonder--just as I do.
When they see me, do they see a liar? (page 1)
The reason that this stands out as notable is that, in portraying a doubting savior, Sanderson has added layers to the generally-absent character's personality. A hero who knows he's a hero is rather simplistic; one who questions his own self-worth while still fighting a battle he's not sure he can win is much more complex and appealing.
In addition, for a writer belonging to a church many would identify as right-wing fundamentalist, this exploration of a hero's self-perception and his role as a religious leader is intriguing. For example, towards the beginning of the novel, the Hero of Ages writes, "Perhaps another person, reading of my life, would name me a religious tyrant. He could call me arrogant. What is to make that man's opinion any less valid than my own?" (page 19) In this instance and in others, Sanderson shows himself to be very open-minded as to others' religious points of view by merely acknowledging that there are other opinions that can hold weight. The nameless author of the journal reiterates his doubts and fears multiple times, including one that closely parallels Nikos Kazantzakis' The Last Temptation of Christ:
Sometimes I wonder what would have happened if I'd remained there, in that lazy village of my birth. I'd have become a smith, like my father. Perhaps I'd have a family, sons of my own.Perhaps someone else would have come to carry this terrible burden. Someone who could bear it far better than I. Someone who deserved to be a hero. (page 276)
If the similarities between the Hero of Ages and Christ ended here, it might be argued that they were purely coincidental. This possible conclusion, however, does not take into account the theme of betrayal that runs through the entire story. Of the the other two main characters (Kelsier and Vin), both deal explicitly with betrayal--Kelsier suspects that his wife turned him in to the Obligators while Vin believes that her brother betrayed her by abandoning her in the streets. Vin even carries this idea so far as to believe that everyone will betray her at one point or another in an uncharacteristically heavy-handed approach by Sanderson.
The entire timbre of the story changes dramatically with this revelation--while it was assumed that the Lord Ruler was the author of the journal, he stood as a character of virtue corrupted by power as he had once foreseen: "I know what will happen if I make the wrong choice. I must be strong; I must not take the power for myself. For I have seen what will happen if I do." (page 577) Instead, the Lord Ruler emerges as a Judas who successfully usurps the role of savior and manages to convince the world that he is Jesus.
 Sanderson, Brandon. "Mistborn: Chapter Thirty-Two." http://www.brandonsanderson.com/annotation/159/Mistborn-Chapter-Thirty-Two