Honest Advisor

""Seek counsel of him who makes you weep, and not of him who makes you laugh.""

- Arabic Proverb

""You're the same way you were the day we met. A pain who speaks the truth.""

- Hiei to Kurama, Yu Yu Hakusho

You've got to pick yourself an advisor, but, you have a problem. Everyone around you is a Yes-Man: spineless, coddling, and/or too concerned with gaining your favor or attaining their own aims to give the truth. But, luckily, there's at least one person who isn't afraid to tell it like it is.

This kind of advisor isn't actually cruel, just blunt and outspoken. They'll never let their charge take the easy way out, and never sugar coat the truth, and never afraid to criticize. As a result, their wisdom is either completely appreciated by their students, or violently rejected if said student is the egotistical type.

If he isn't a mentor, but a regular part of the group instead, then he's usually the Deadpan Snarker, the constant criticizer, and more or less the one that annoys everyone but still gets their complete respect. All in all, this is who you want when it comes to finding a most trusted ally, and it's probably better to find people like this than your average minion.

Often the role of The Jester in a royal court, getting away with mouthing off to the king either by couching criticism in satire, or by being (or appearing to be) mentally incompetent and thus not a threat. Another term frequently used in the past was "Naysmith" (which survives in the modern surname Naismith), meaning the one person in a royal court who could openly say "no" to the king's plans without fear of censure, forcing the king to accept criticism--the opposite of a Yes-Man.

See also Hire the Critic and The Consigliere.

Anime and Manga

 * Genkai in Yu Yu Hakusho is one, whose favorite pastime is to call her student a dumbass/moron/dimwit/etc. and outline just how stupidly he's dealing with the current situation. All in all, she isn't afraid to trick, insult, or nearly kill Yusuke if it means he'll finally stop fooling around and see things clearly.
 * Also Kurama, who is both kindhearted and brutally honest, due both to hundreds of years of experience being a bandit and to experiencing the redeeming Power of Love firsthand.
 * Code Geass: CC is this to Lelouch.
 * Not a perfect example though, because while she is generally honest, she also has a habit of withholding important information as well.

Comic Books

 * Batman: Alfred is like this to Bruce Wayne, and, as a result, he's one of the people Batman respects the most.

Film

 * Daine Jir, an Imperial officer from the first Star Wars. He only appears in one scene, but he criticizes Darth Vader to his face and Vader listens.
 * Vader always listens to his stormtroopers and fighter pilots, the people on the front lines. He just doesn't get along with anyone else.
 * Tiberius' advisor Nerva in Caligula is put-upon and frequently disregarded, but valued for being the only man Tiberius trusts and respects. When it looks like Caligula will inherit, he decides he's had enough and takes a suicide bath.

Literature

 * Niccolo Machiavelli advises princes to avoid flatterers, although their advisers shouldn't be seen as disrespecting them either.
 * William Cecil does this for Queen Elizabeth I in Phillipa Gregory's The Virgin's Lover. Not sure how close to the truth the book is though.
 * The prophet Nathan to David in The Old Testament, making this Older Than Feudalism.
 * Discussed in the Dystopia novel The Unincorporated Man. When the main character becomes the leader of a group of rebels, he has a Black Shirt as his advisor, because he thinks the group is out of touch with what normal people think. (Mind you, he's smart enough to choose someone who considers him a friend and won't betray him.)
 * In A Song of Ice and Fire, Davos Seaworth is this to Stannis Baratheon.
 * King Robert calls Ned Stark to the south to be this. Stark nearly loses his job for doing it too well.
 * In Mercedes Lackey's Heralds of Valdemar books, it is built into the Heraldic system that the King or Queen always has a Monarch's Own Herald, ready to serve as trustworthy friend, confidant, and brutally honest advisor if needed.

Live Action TV

 * DS Barbara Havers is this to her partner, DI Lynley, on The Inspector Lynley Mysteries. Although it took her some time to earn the position, by the end of season two she can get away with saying things no one else could because she has earned his trust repeatedly over the course of their partnership, and though he might snap at her, she knows that's as far as it will go.
 * Londo Mollari in Babylon 5 is unhappily married to three wives: One (Timov) who unabashedly criticises him at every turn, and two others (Muriel and Daggair) who act nice to him in person while plotting behind his back. When he's permitted to divorce two of the three, Timov is the one he keeps even though she's given him no reason to like her.

Video Games

 * Soren in Fire Emblem: Radiant Dawn (GC).

Web Comics

 * Baron Wulfenbach in Girl Genius states early on that he prefers his men criticize him when possible, rather than see flaws but be too afraid to voice them.
 * Also, Agatha and Gil seem to prefer to have advisors who know how it is and aren't afraid to tell them off as well, Agatha with Von Zinzer, while Gil nearly always works with close friends rather than minions.

Western Animation

 * Jiminy Cricket is like this for Pinocchio.
 * On The Simpsons, Mr. Burns hired Lisa (who hates him) as his assistant after listening to his yes men caused him to lose his fortune.
 * The reason Foghorn Leghorn keeps taking Daffy Duck under his wing in The Looney Tunes Show.
 * Applejack from My Little Pony Friendship Is Magic would be this if she had any interest in politics. However, she played one in the Christmas episode. But the leader she served was such an arrogant nutjob that she had long since degenerated into a Deadpan Snarker.

Real Life

 * Simon Cowell: "I'm not being rude, but..."
 * Italo Balbo, The Dragon of Benito Mussolini, who didn't trust the Germans and advised Mussolini to continue with the alliance with France and maybe build up an alliance with UK as well. Mussolini refused and Balbo answered with "You will all wind up shining the shoes of the Germans". Guess what Mussolini's last job was.
 * Piñata?