The Jailer

"Batman: I've seen how you treat your prisoners. Forgotten and scared, without hope or compassion. Lock-Up: And you actually care for those creatures? You're just as crazy as they are!"

- Batman: The Animated Series, "Lock-Up"

A vigilante, usually a Knight Templar or Well-Intentioned Extremist, who, rather than killing his chosen targets, imprisons them.

Anime and Manga

 * In Kanokon, Yatsuka-sensei and the other nonhuman monsters' job is to make sure the nonhuman students stay put and don't break The Masquerade until they've figured out how to fit in with humans.
 * Oldboy features a prison for people who need to get rid of someone but don't have the skills or the will to kill. The main character, in Chapter 1, is dumped back into the real world after fifteen years.

Comic Books

 * Locksmith in the Marvel Universe who used to imprison super-humans.
 * The Hangman, another Marvel Universe vigilante, would murder male evildoers but imprison female ones to 'protect them from corruption'. Unfortunately, he had a nasty habit of forgetting about them, leaving them without food or water...
 * In the Marvel 2099 universe, the Punisher (2099 version) had his own private prison. Of course, in his Cyberpunk Dystopia Crapsack World, anyone who could shell out the fine could get away with any crime, including murder. This made him - relatively speaking - as much an extremist in his world as the original Punisher (who just shoots everybody) was in his. Possibly more so; his prison came with a torture chamber. By the way, he reserved his prison for offenders whose crimes he felt didn't quite deserve the lethal approach - this was actually his idea of mercy!
 * Rayek in Elf Quest, who never wanted to kill Winnowill (partly because he loves her, but mostly because if she dies her evil soul will be free to wreak havoc), and in the end becomes her living jailer,
 * Faora Hu-Ul was a Phantom Zone villain introduced in Action Comics #471. She was a beautiful Kryptonian woman whose unexplained hatred for men led her to torture and kill 23 men at a secret concentration camp in her home.
 * Lyle Bolton, alias Lock-Up, from Batman.
 * The Master Jailer from Superman comics is a sort of example, except he's an out and out villain who just likes the power trips provided by his powers. And of course he's an unusual example because he actually has powers to facilitate his fascination with incarceration. Also of note is the fact that he was the architect who designed the supermax prison in Metropolis, Stryker's Island.
 * Mr Smyth from Secret Six, a slave trader who was building what he hoped would be the world's biggest and only prison.
 * Grimbor the Chainsman from The Legion of Super Heroes.
 * The Batman of the future in DC One Million runs the Solar System's hypermax prison facility, deep within Pluto.

Literature

 * A borderline case occurs in the Young Bond novel Hurricane Gold by Charlie Higson. The main villain El Hurrican runs an island hideaway for criminals on the run. Once on the island, they can never leave. While their money lasts, they live a life of luxury, but once their money runs out, he puts them to work as a slave labour force. El Hurrican does confide to a youthful James Bond that he regards himself as the jailer of these criminals.
 * In Soon I Will Be Invincible, major supervillain Baron Ether lives out his twilight years under house arrest in his mansion, with his nemesis The Mechanist as his jailer.
 * Although he's not doing a great job. While Baron Ether never tries to break out, people keep breaking in to see him.

Tabletop Games

 * Torog, Evil God of the Underdark. Patron of Jailors and Torturers.
 * The Mutants and Masterminds Freedom City villain Warden is one of these. He worked on making prisons as non-cardboardy as possible, and got a bit fed up with people making that task harder by telling him that the prisoners have rights; didn't they forfeit those when they ended up in prison? His current goal is to overthrow "soft and corrupt" law and replace it with something altogether more draconian.
 * Yu-Gi-Oh! Rush Duel sets have Dian Keto the Security Master; given that she has a riding crop and is shown arresting and restraining Sparkhearts Girl and Whispering Fairy in Pretty☆Witch Imprisonment and Last Day of the Pretty☆Witch (monsters used by the protagonist) show she's not the most benign corrections officer. There are also her cohorts, Karen the Warden Mistress and Enguarding Mermaid.
 * This is emphasized by the way the Solid Vision system interprets the effects of Mimi's cards in Yu-Gi-Oh!: SEVENS in her duel with Roa, which takes place in a large stadium. The Field Spell she uses ("Prison Island Ane Go Rock") places them on platforms in a lake in the center of a prison, putting the spectators in the cells (including her allies from the Goha Corporation, one of whom even says she's getting a little carried away) while Dian Keto's effect (which sends a monster in Roa's hand to the Graveyard) is illustrated by Dian Keto putting the unfortunate monster in another cell. This all seems sort of entertaining, but takes a horrific turn when the Goya Drone she's wearing decides to get serious and not only use Mimi as a Brainwashed and Crazy slave, but use a monster that does the same to Dian Keto.

Toys

 * Hydraxon from Bionicle. To be fair, it is his job description, and he's hunting escapees in a place where he can expect to find only escapees, but he's still a little too quick to assume that everyone he meets is an escaped criminal. Botar, in charge of prisoner apprehension and transport, also liked his job a bit too much.

Video Games

 * The Ur-quan Kzer-za in Star Control 2. Either you joined them, or you got slave-shielded and trapped on your home world.
 * Warden Kuril from Mass Effect 2

Web Original

 * Der Fallensteller ("The Trapper") is a German superhero from the Global Guardians PBEM Universe. He is a Gadgeteer Genius who specializes in traps and bonds.
 * SCP Foundation has, well, the Foundation. "SCP" stands for "Secure, Contain, Protect", meaning they Contain abnormalities in order to Protect the public from them (and in many cases, they do it to protect abnormalities from the public). Usually, this means capturing and jailing them. (Unlike their rivals the Global Occult Coalition, who usually have a more permanent solution in mind.) In fact, their enemies the Serpent's Hand calls them "The Jailers".

Western Animation

 * Lock-Up from Batman: The Animated Series (and Canon Immigrant to the Batman comics). In the animated series, Lyle Bolton was once the new Head of Security at Arkham Asylum, but whose methods were so harsh and extreme that everyone at the asylum was afraid of him, particularly Scarecrow. After being relieved of his post, he would go on to "arrest" those who he deemed to be at the root of Gotham's problems, including the mayor, Commissioner Gordon, reporter Summer Gleeson and the chief doctor of Arkham (coincidentally the very same people who exposed his abuse of power and had him fired) before being stopped by Batman and Robin.
 * Rumour from The Batman is similar.
 * Danny Phantom has Walker, the obsessive sheriff type.
 * One episode of Gargoyles turns Goliath into this when he uses Odin's Eye to become a Physical God. The best way to "protect his friends" is to seal them in a cave for the rest of time. Nothing can get to them there.
 * Mr Moss from Storm Hawks.
 * The Warden of Superjail It's not like he's trying to uphold the law or anything. It's mostly because he loves incarceration that freaking much.
 * Avatar: The Last Airbender: Hama.
 * Played with in ReBoot when Megabyte imprisons Hexadecimal when he's not exploiting her power. When the firewall goes up imprisoning Megabyte, Hexadecimal remarks "now it is the jailer who has been jailed."
 * Kampe, the jailer of Tartarus in Class of the Titans. Cronus was the only prisoner to have ever escaped under her watch. She hopes to correct this, even if it means sacrificing others to do so.
 * The first villain in The Owl House is Warden Wrath, a fiendish creature who captures and locks up folks who he deems "weird". (As in, he thinks social non-conformity is a crime.) Fortunately, he proves easily subdued after Luz frees his prisoners and gives them a much needed pep-talk.
 * Parasite in Superman: The Animated Series. His ability to drain a victim of memories, skills, and super-powers is temporary, so he tends to hold them hostage so he can use them to "recharge" periodically. Unfortunately for him, Superman isn't exactly a cooperative prisoner.