Publication Information
- Supergirl : Carl Draper
- Version : Supergirl
- Alter Ego : Master Jailer
- Multiverse : Earth Thirty-Eight
- Spieces : Trombusans
- Known As :
- Type :
- Affiliation :
- Gender : Male
- Origin : Fort Rozz Prison
- Season : Supergirl
- First Appeareance : Supergirl Season 1 Episod 14 : Truth, Justice and the American Way
- Last Appeareance :
- Number of Appeareance :
- Potrayer : Jeff Branson
- Main View : Full Episod

Carl Draper on Earth is a Trombusan prison guard that worked on Fort Rozz. The Master Jailer is a former guard at Fort Rozz who hailed from the planet Trombus. He masqueraded as Carl Draper, a National City police detective, while hunting down and killing the Fort Rozz escapees who were disguising themselves as Earthlings. He made use of advanced alien technology, including an armored suit that made him a match for Supergirl physically.
Master Jailer

Abilities
- Trombusan physiology : As a Trombusan, the Master Jailor seems physically indistinguishable from humans, which allowed him to infiltrate the National City Police Department as "Carl Draper". It is currently unknown if it possesses any superhuman abilities beyond his armor's capabilities.
- Hand-to-hand combatant : As a former prison guard at Fort Rozz (prison), the Master Jailer demonstrated skill at hand-to-hand combat, being able to defeat and restrain Supergirl twice with the use of his combat skills and his suit's weaponry.
- Skilled marksman : Under the guise of police detective "Carl Draper", the Master Jailer showed skill in the use of a handgun, shooting both his partner, Jim Warren and Alex Danvers, the latter of who was protected by her bulletproof vest. He also managed to easily knock down Alphonse Luzano by throwing his baton several feet at his feet.
- Master Jailer Armor : The suit used by the Master Jailer was an advanced battle armor capable of physically enhancing its user to be able to fight Kryptonians, though it does not necessarily make him strong enough to overpower one as he could be fought off briefly by Alex Danvers. Additionally, the Master Jailer demonstrated the ability to fly, shoot energy blasts from his forearms, and project super-strong chains. Its energy blasts and chains where notably used incapacitate Kryptonians, along with several aliens, with ease. Under his human guise of "Carl Draper", the suit collapsed into pieces and concealed itself on its user, while the entire helmet could collapse itself without the rest of the suit to reveal his face.
- Baton : The Master Jailer threw a baton at the feet of Alphonse Luzano to knock him down. J'onn J'onzz described it as being made of an alien material called "black star alloy" when it was recovered by the D.E.O. and used to find out that it was standard police issue.

Trombus

Publication Information
- Supergirl : Trombus
- Version : Supergirl
- Multiverse : Earth Thirty-Eight
- Type : Planet
- Spieces : Trombusans
- First Appeareance : Supergirl Season 1 Episod 14 : Truth, Justice and the American Way
Current inhabitants
Trombusans

Publication Information
- Supergirl : Trombusans
- Version : Supergirl
- Multiverse : Earth Thirty-Eight
- Type : Humanoid
- Origin : Trombus
- First Appeareance : Supergirl Season 1 Episod 14 : Truth, Justice and the American Way
- Despite hailing from another world, Trombusans are indistinguishable from humans.
- They are a technologically advanced race utilizing advanced weaponry such as the Master Jailer armor