Non-POV Protagonist

Some written works feature a consistent Point of View: namely, through the eyes of The Protagonist. Other works throw in additional protagonists and pass the POV around to present each of their respective views on the transpiring events. Sometimes, however, a single main character (usually the one with the most ambiguous/mysterious motivation) is conspicuously denied POV and their impact upon the plot is only ever seen through the eyes of co-protagonists. This character is the Non-POV Protagonist of the book.

The main purpose of the trope is to create dramatic tension. When a the story is told from the perspective of a character, readers become very familiar with him or her, and can make some predictions as to their feelings and reactions. When a the story does not give the perspective of a character, readers are left peering in, wondering just what is going through that person's head. That can be quite a tense experience if said character is The Chosen One, the Big Bad, or even just a Supporting Leader who will nonetheless be making decisions that the narrator characters have to live with.

Due to the nature of the medium, this is primarily a Literary Trope, though media closely related to literature may also use it.

Related tropes (that often accompany this) include Supporting Protagonist, a POV-character who is a protagonist, just not the "main-main" one; and First-Person Peripheral Narrator, a narrator character who isn't a protagonist. In those terms, this trope describes a "main-main" protagonist who isn't a POV-character.

Literature

 * In A Song of Ice and Fire, Robb is the only Stark child besides 4-year-old Rickon to never have his own narrative, despite having major events in A Clash of Kings and A Storm of Swords revolve around him. Most of the chapters involving Robb are told from the P.O.V. of his mother.
 * Robb? Heck! All four Baratheon kings (Robert, Stannis, Renly and Joffrey), Tywin Lannister, Petyr "Littlefinger" Baelish, Varys the Spider... Wildly important characters, and not a damn one of them narrates.
 * Played strait in books 2 and 3 but subverted in book 5 with Melisandre. Her lack of narration in 2 and 3 contributes to the overall mysteriousness of the character.
 * Roque Alva is arguably the central character of the Reflections of Eterna cycle, yet there has never been a single chapter describing what exactly is going on in his head.
 * The Sister of My Sister's Keeper is, until the very last chapter, the only main character that doesn't narrate a chapter. The book only has a few characters, and asides from Kate, the only characters who don't get to narrate are the Judge, a bartender named Seven, and a dog.
 * A similar thing happens in Handle with Care, when, until the last chapter, everyone but Willow (the main reason for the plot) narrates.
 * Due to the fact that she's dead, the mother in As I Lay Dying never narrates a chapter. Again, given the fact that she's dead, this isn't unusual until you consider the title.
 * Andrew Jackson is treated like this in Trail of Glory. It might be argued that he is the most important character in the story, but we always see him from the outside.
 * We never get Sherlock Holmes's point-of-view in all but two of his mysteries, only Watson's.
 * Similarly, Erast Fandorin has only been the POV character in five out of thirteen books about him.
 * Caddy from The Sound and the Fury is the only one of the Compson children without her own chapter.
 * Carrot Ironfoundersson from Terry Pratchett's Discworld books. He's an important character, yet we never see what he thinks. Other main characters' POV are frequently presented. There's a theory that this might be due to the fact that he's not exactly as innocent and simple - minded as he appears to be, and Pratchett doesn't want to show it.
 * Carrot gets occasional POV sequences - the first little bit of Guards Guards and the odd page or two in other books are through his eyes. Vimes is just a much more interesting character.
 * Admiral Thrawn from Star Wars Expanded Universe. He's an Anti-Villain antagonist, to be precise, but we have narration from the POV of Imperial characters - except him. Never from his point.
 * Happens in Stargirl by Jerry Spinelli. Leo talks about his Manic Pixie Dream Girl friend Stargirl, but she never narrates. Sort of inverted in the sequel, Love, Stargirl, where Stargirl narrates and discusses her relationship with Leo but he never narrates.
 * Many important characters in The Lord of the Rings are narrated by hobbits. (Not that the hobbits are unimportant, but since a Supporting Leader is often a Non-POV Protagonist and Aragorn son of Arathorn is the original Supporting Leader, it bears mentioning.)
 * Miranda Sharifi in Beggars and Choosers, second book of the Beggars in Spain trilogy.
 * The character Kitai in Codex Alera is arguably one of the most important characters in the series (let's count the number of times she saves Tavi's life...) and faces many important and interesting decisions throughout the series. However, the reader always sees her actions through Tavi's and once, Isana's eyes. Bernard is like this as well.
 * Malazan Book of the Fallen: While the author almost zealously ensures that most named characters are given a point of view section regularly - not a mean feat, considering that there are usually hundreds of characters that qualify - Tavore Paran is a notable exception. Throughout the series we are given only a single paragraph from her point of view, and a vague one at that. This is deliberate; she is one of the series' greatest mysteries.

Video Games

 * Thanks to some Leaning on the Fourth Wall in the Baten Kaitos series, the player him/herself is the point of view character, being cast as the "Guardian Spirit" of Kalas (EWatLO) and Sagi (Orgins). While the two are the main characters of their game, they are not the POV characters, a distinction that has some very interesting effects in Eternal Wings and the Lost Ocean as.
 * Masterfully played in Heavy Rain: you can overhear the thoughts of every character but one of them never shows their true feelings even when thinking. So, in effect, you get a protagonist whose POV you think you know but you really don't until the end.
 * Princess Ashe is the real hero of Final Fantasy XII, but the game's story is told through the eyes of Vaan, a street rat who stole the right MacGuffin.
 * Final Fantasy Tactics: Delita, despite being the Deuteragonist and having plenty of screen time, is largely left a mystery as most of his scenes are seemingly seen from the perspective of other people present, most prominently the Princess Ovelia. There are a handful of exceptions, and he does have a few scenes which focus on his personal affairs, but even then very little is revealed about his true self.

Visual Novels

 * Higurashi has a unique way of letting you see through the character's eyes. You get to see it through the new kid's eyes, the twin sister's, the crazy girl's, etc. But you never get to see Sonozaki Mion's point of view. Or Satoshi's. Or Hanyuu's.
 * Nogizaka Haruka no Himitsu is, as those who read Japanese must have figured out from reading the title, about the secret of a character named Nogizaka Haruka. However, the story isn't told from her P.O.V., but the one of Ordinary High School Student Ayase Yuuto and is about how his life changed after learning the secret.