Claustrophobia: Not completely explained on this book, but closed spaces are not his style. We are informed of this when he gets locked in a library with a limited supply of air. He still manages to keep his cool to escape, thanfully.
Enemy Mine: Thanks to his past, he has nothing but hate and disgust for everything religious. But he can't just let people die as result of a terrorist attack.
Hollywood Atheist: Kohler's reason for being atheist was that his parents, instead of getting him the right medicine for a crippling, life-threatening illness when was young, decided to pray over him. He only survived because a doctor injected him with the medicine without his parents' knowledge. The whole ordeal left Kohler paraplegic. To top it all off, when his parents took him to a Priest to ask why their son is crippled, the priest berates him for not having enough faith. He became very bitter, to say the least.
Sure, he didn't plan on dying in the process, but the Camerlengo does manage to achieve pretty much all his primary objectives. He successfully jump-starts a worldwide renewal of faith in Christianity's power, while simultaneously causing popular distrust of the scientific community. In the book, as far as the masses are concerned, he even goes down in history as miraculously ascending to Heaven. And Langdon and Vittoria can never tell the world the Illuminati were a sham and the entire drama was a dog-and-pony show by the Camerlengo, because disllusioning the people just as they've had their faith restored would do more harm than good.
The movie sidesteps this one, Langdon manages to save Baggia, who later becomes pope under the name Luke (after the physician and evangelist). The movie manages to have it both ways, a pro-science pope and the renewal of faith.
Big Bad: He manages to be this with his incredible capacity for manipulation.
Bitch in Sheep's Clothing:God damn. The trope should be renamed The Camerlengo. He would have played everyone for fools if Koch wasn't filming their conversation.
Chekhov's Skill: The Camerlengo is trained as a medical helicopter pilot. This comes in handy later, when he disposes of the anti-matter bomb.
The Chessmaster: There's no Illumminati. There's only him and the Hassassin, and the Hassassin thinks he's working for the Illumminati.
Freudian Excuse: Averted with his mother's death as the result of an terrorist attack. What truly sets him in the path of unspeakable evil is discovering that the Pope had a son(that to his own horror is him) and the discovery of Vetra that launched him on a crusade to make science look evil and religion good.
The plan depends on the Camerlengo being NOT seen by Langdon and getting to the Anti-Matter, which he placed on Saint Peter's catacomb, on time. Needless to say, he's spotted by Langdon, and was interrogated by Kohler (who caught the whole thing on tape) before Kohler was shot.
It's Even less plausible in The Film of the Book, where The Plan is for Langdon to find the antimatter mere minutes before it detonates. A few minutes too soon, and the bomb is easily defused. A minute too late, and St. Peter's is destroyed, along with the Camerlengo. And that's just the most obvious flaw in the hilariously roundabout plan. Spotting the rest makes for one Hell of a drinking game.
Genghis Gambit: What the Camerlengo does in the movie with the Illuminati.
In the film, the Camerlengo gets one to the Cardinals about how the Church is just trying to be a beacon of salvation and solidarity in a world growing increasingly amoral under the influence of technology, and that world outside needs to realize the Church for this and not see them as some sort of archaic cult. Subtle, isn't it?
And another one in the movie when he's confronted by Richter. By the Camerlengo's twisted morality, science shouldn't be allowed to prove the God Particle's existence and "reinvidicate the miracle from creation from God", which makes his previous speech to the cardinals even more bullshit. In both cases, he's basically spouting that science should only be allowed to work under religion's thrall.
Poor Communication Kills: If the poor Camerlengo had really listened to the Pope's full story, none of this would have happened.
Religious Stereotype: He avert this completely, being a kind and respectable member of the Church, and he is such a Hope Bringer that the cardinals even think in making him Pope, and in fact do it through proclamation. Then he plays it so straight that makes the Hassassin look moderate.
The Messiah: Plays it straight,as weird as it sounds. Turns out he deliberately invoked this on himself to renovate faith on the Church. Talk about being blasphemic.
Xanatos Speed Chess: Indicated in the movie when the Camerlengo says to Richter "I was planning on doing this alone, but perhaps it's better that you're here." Just before branding himself with the upside down papal symbol.
Enemy Mine: He is much of a radical muslim as you can imagine in the book. He is only fighting for the Illuminati because he sees the Catholic Church as a bigger threat to eliminate. Averted on the movie, where he isn't only aware of working for a member of the Catholic Church, as the Church has already hired him to kill people before and don't even seems to be muslim.
In Name Only: If the hitman didn't fulfill the exact same role of The Hassassin, they wouldn't share a character sheet in first place.
I Shall Taunt You: Taunt the heroes over the antimatter bomb and what will be the effects of the explosion on the financial existence of the Catholic Church around the world, and the fate of the prefertiti, and Vittoria in special over her father.