Zen Survivor

"Endure. In enduring, grow strong."

—Dak'kon, Planescape: Torment

A character who has been through utter hell, and came out sad, cynical, and Wise Beyond Their Years. Part of their wisdom is knowing that it is wasted on most people, so they don't go around babbling it to everybody (that's for the Nietzsche Wannabe). Instead, they wait until they see somebody who is worthy, and serve as the worthy one's Mentors.

Like an ancient Zen master, a Zen Survivor never gives straight advice. Instead they speak in odd riddles and hints, delighting in Cryptic Conversation. They also make bizarre demands, and do cruel, seemingly pointless things to their student. This is because (also like a Zen master) they have an Omniscient Morality License. They know not just the world but their student better than the student does—each of their cruel tests is designed to teach a lesson, and the lesson is always right.

Usually, the Zen Survivor does this because simply giving advice doesn't convince anybody, while odd tests do. If their student is too stubborn to believe them, the Zen Survivor will pretend to give in... and provide just enough rope for the student to hang themselves. Inevitably, the student will come crawling back.

Distinct from the Dungeon Master in that they hold back knowledge, not talents or powers.

The Zen Survivor can also be evil and generally realize it themselves, but they justify their actions on the basis of ruthless pragmatism (often in the name of the greater good).

Examples of Zen Survivor include:

Anime and Manga

Urahara's Training from Hell and tragic backstory seem to qualify him.
Shogo Kawada in Battle Royale, "winner" of a previous year's Program.
Gordon Rosewater from The Big O is a low-key example: he built Paradigm City and retired to become a farmer, leaving it in the hands of his son (who has since become the Big Bad). Gordon is fully aware of how evil and stupid his son is, and gives Roger advice on how to deal with him—but always cryptically, so Roger can Figure It Out Himself and thus use it better. Gordon also knows the secret of the show's Ontological Mystery, but is just as cryptic about this.
Archer from Fate/stay night is the incarnate of this trope, from his hellish past down to the twin-dao falchions he wields. He constantly gives Shirou 'advice' in the form of insults and degrading comments (and at least a few cryptic lines here and there), because as Shirou's future self, he knows exactly what Shirou needs to learn or do to improve himself, or at least how to avoid the path that Archer took.
Gatomon from Digimon Adventures entire backstory is made of this trope, and is worth to menction that she also gained Genre Savvy status during the sequel.
Gendo Ikari from Neon Genesis Evangelion. A bitter, hardened genius who forces his son Shinji to go through hell 'for his own good' -- and it's kept unclear until the very end whether it really is for Shinji's own good or just evil.
Tengen Toppa Gurren Lagann with Lordgenome. The Anti-spirals almost, but not quite, fit as they foresee the hell down the road and stop themselves before reaching it. Then simply kill anyone who nears their road block. If only they were a bit vague in their answers once they did talk...
Monster has a nod to this trope with Wolf, Rosso, and even Bonaparta.
- Runge gets in on the act as well.
Kirby: Right Back at Ya! has Metaknight, who often acts this way to Fumu (and sometimes Kirby).
Neo Roanoke of Gundam Seed Destiny functions as a really, really evil one to the three Extended, all while still projecting the Big Brother Mentor vibe he gave off in the previous show. The results are not pretty.
Puella Magi Madoka Magica has one in Homura Akemi, who is one of the magical girls. This should give you an idea of what kind of show it really is.
"Dark Prince" Silver Rayleigh takes this role to Luffy in One Piece. He was the vice-captain of the Gold Roger Pirates, has been to the New World and back, and now spends his times at a bar, fairly annoyed by the new age of pirates coming and going. He takes a liking to Luffy, and after the Marineford War arc, takes two years to teach Luffy how to use haki.
Itachi Uchiha from Naruto fits this trope to a T. He's been through more hell than almost any other character in the series, and that's saying a lot. First he was caught in a war at the ripe old age of four, then he was forced to kill most of his clan, induce the hatred of the only family he had left, and leave the village and fend for himself among terrorists who alternately threatened him or outright tried to steal his body, all with his massive trauma totally untreated. To make matters worse, he had to pretend to be OK with this for eight years afterward, while trying to avoid killing the people who attacked him without realizing he was on their side. All in all, it's a wonder he even cares enough to bother giving people like Naruto and Sasuke warnings, cryptic advice, and bits of power in the form of transplanted eyeballs and force-fed crows.

Film

In the sequel to Kung Fu Panda, of all places, Master Shifu tells Po that some masters achieve inner peace through great pain and suffering.
Tyler Durden from Fight Club. He uses bare knuckle boxing, chemical burns, car crashes, and terrorist activity to mold the main character into a more confident, assertive, and fulfilled person.
Star Wars has both Obi-Wan Kenobi and Yoda. Obi-Wan, in particular, shows a stark contrast from his sarcastic Cynical Mentor persona in the prequels to his wise, peaceful older self in the original trilogy.
In The Mask of Zorro (1998), the original Zorro, Don Diego, plays this role.
Sue in The Rage: Carrie 2. She was one of the few survivors of Carrie's rampage in the original film, and is now a school psychiatrist. When she learns about Rachel's powers, she immediately steps in to try to help her, hoping to prevent her from going nuclear like Carrie did. She fails, and gets killed for her effort.
The version of Pei Mei seen in the Kill Bill movies fits this trope. He is pretty nasty and cruel but he's been isolated so long that he can at least value a little company so he takes students.
This is what Sidney Prescott becomes after surviving the horrors of the Scream movies, specially after the events of the second movie. Poor girl needs to catch a break.
Kevin Flynn in Tron: Legacy, as compared to the brash, headstrong person he was in the original.

Comics

Uncle Scrooge has gone through several levels of hell in The Life and Times of Uncle Scrooge. He usually allows Donald Duck to get into trouble knowing the lessons will be worth it. "Someone's about to learn a lesson lads." What's more, Donald and his nephews are worthy of Uncle Scrooge's wisdom and money... he'll just never tell them that.
High school outcast Shelley in The Underburbs.
V in V for Vendetta. Though not as much in the movie.

Literature

Robert A. Heinlein's Lazarus Long is a Zen Survivor. Over two thousand years old, his utter hell has been watching the people he loves grow old and die while he lives on.
Armitage in Neuromancer, the first book in William Gibson's Sprawl Trilogy.
Thorkell, the burnt-out Erling raider in Guy Gavriel Kay's The Last Light of the Sun. He's old, tired, estranged from his son, and all but ready to go. Yet despite this, he's oddly at peace with the world, figuring that whatever happens, happens, and spends most of the book as an odd sort of Mentor to Alun and Aethelbert, who can desperately use the guidance.

Live Action TV

Buffy the Vampire Slayer subverts this with the Watcher's Council, who do cruel, apparently stupid things "for the Slayer's own good" that turn out to be... just cruel and stupid; naturally, Buffy tells them off and mutinies.
Ellie Nash in her early appearances on Degrassi the Next Generation was a grim goth/punk who befriended fallen popular girl Ashley and taught her how to cope with life as an outcast. Ellie rarely spoke, and stood up to The Alpha Bitch by simply refusing to obey, without arguing. She would often follow Ashley while silently nodding or shaking her head. In one episode, Ashley tries to make up with her old friends but fails—and the camera panned out to reveal Ellie, who made a dry, almost Zen-like remark about the futility of popularity in school.
- When Ellie evolved out of this part, other Degrassi characters took her place. At various points, Manny, Tracker, Ashley, Spinner, Jimmy, Paige, and Alex have all become a Zen Survivor (and ceased to be one after a few episodes).
"Claude Rains" from Heroes: his training of Peter is brief, brutal, but very helpful (though he gets some things wrong), and he definitely fits the Backstory requirements.
Charlie Crews, the hero of Life, a homicide detective wrongfully accused of murder but proven innocent after 12 years of hard time, is explicitly into Zen, although in his case somewhat twisted as he did go a bit nuts in the Big House.
John Locke on Lost comes close to this trope. His life pre-island was phenomenally depressing, but on the island, he arguably has the most key moments of the main cast (he ranks at least third to Sayid and Sawyer), and even has a few bizarre tests to put other characters (and sometimes even himself) through. He's also got a strong cryptic streak.
Ashley from South of Nowhere is a high school girl with negligent parents who had a miscarriage, lost her boyfriend, and came out as bisexual—all during the Backstory. She serves as a teacher and love interest to the heroine, teaching her about sexual orientation and what kind of people can be trusted. Ashley abuses her Omniscient Morality License to absurd levels—anything she does, no matter how callous, is always for the best.
Methos in Highlander is one of these, and much like the page quote has a piece of wisdom he regularly trots out that goes 'Live, grow stronger, live another day'
Babylon 5's Commander Jeffrey Sinclair is very much one of these as Entil'zha of the Rangers.
Lionel Luthor of Smallville is this to his son, Lex Luthor. By screwing with Lex's head, Lionel hopes to turn his son into the man he always wanted him to be.
The title character in House is this to pretty much everyone in the show, but particularly to whoever is playing the Moral Guardian this season.

Video Games

Final Fantasy X's Auron plays the obvious mentor in the game's tutorial, and after a temporary disappearance, joins the party after a crisis as a powerhouse fighter and the cryptic, all-knowing stoic. It's understandable why: after going through the grueling Summoner's Journey once, he underwent The Reveal that the entire religion was a hoax and had to witness his Summoner get murdered while his other Guardian was turned into the next beast to torment the universe. Oh, and Yunalesca kills him for good measure. He then is charged with living in Fake Zanarkand for a decade to tutor Jecht's son.
Snake of Metal Gear Solid is generally aloof and cynical around his impromptu protege love interest throughout the course of the game. He gets some perspective on his life through the process, and becomes a mentor in the sequel.
In Planescape: Torment, one of the NPCs you can add to your party, Dak'kon, is a weathered old githzerai who follows a path of wisdom that relies on hidden truths and occasionally contradictory secrets. However, if the player character becomes intelligent and wise enough, he can turn it around and start teaching the Zen Survivor. Of course, given the player character's backstory, he could easily be something of a Zen Survivor, too... It turns out the path of wisdom he follows was made by you in the past, albeit only as a way to ensure Dak'kon's eternal loyalty towards you.
Medivh from Warcraft, as of the third game. After being defeated in 1, he makes a Heel Face Turn, and becomes a prophet, uniting the three living races (orcs, humans, night elves) against the Scourge. His role in World of Warcraft seems to be less prominent.
Marlowe in Visions & Voices.
Nessiah in Blaze Union. Jury's out on whether he's actually evil or just kind of messed up, but depending on the route he's either the team's mentor or the antagonist.
Kreia from Knights of the Old Republic II could practically be this trope's patron saint. She's both a fallen jedi and a fallen sith and now occupies a strange middle road in the Force, dispensing her bitterly-earned wisdom to the main character.
n in Togainu no Chi, albeit less so in his own route.
Samara in Mass Effect 2, an asari Matriarch who is an ascetic warrior-monk hunting down a mass-murderer who is her daughter.

Webcomics

From Girl Genius, Klaus Wulfenbach. Having to go through the pain of a world destroyed by pointless wars made him a bit more cynical. Surviving his lover and a few of his close friends also jaded him. In a slight subversion, he doesn't passively dole out advice. He uses his knowledge to seize and 'fix' the world. The motto on his empire's flag is "Don't make me come down there."

Real Life

Older Than Feudalism: Socrates is reputed to have been one of these. An anecdote says that a casual student approached him for schooling. Socrates invited the boy to sit along the river beside him. When the boy's guard was down, Socrates grabbed him and plunged his head underwater and held it there. When the boy was let up, spluttering and dripping, Socrates calmly asked, "So tell me, what did you want most of all while you were down there?" The boy gasped, "Air!" Socrates said then, "Come back to me when you want to learn as badly as you wanted air."