|“||I'm a child of the Slitheen and this is my hunt||„|
Korst Gogg Thek Lutiven-Day Slitheen is the 12-year-old son of Kist Magg Thek Lutiven-Day Slitheen, the nephew of Glune Fex Fize Sharlaveer-Slam Slitheen, a member of the Slitheen a criminal family from Raxacoricofallapatorius, the tertiary antagonist in The Sarah Jane Adventures episode Revenge of the Slitheen and the main later true secondary antagonist (the real main antagonist being Mr. Smith) of The Lost Boy.
As Carl, he is played by Anton Thomas McCormick whilst as Nathan, he is played by Ryan Watson. Both actors voice his Slitheen form which is played by Jimmy Vee.
Not much is known about Korst but that sometime in 2007 as for his first hunt he travelled to Earth with his father, uncle and several other members of his family who took over a building company called Coldfire Construction and placed transducers around Earth to absorb the Sun's energy and destroying Earth as part of the plan to avenge the deaths of the Passameer-Day branch of their family who died after they were killed by a missile in 10 Downing Street in the Doctor Who episode World War Three.
Revenge of the Slitheen
|“||That's not fair Daddy. That woman cheated. I want my hunt!||„|
|~ Korst to Kist after Sarah Jane helps Luke, Maria and Clyde escape|
18 months later in September 2008, some members of the Slitheen when under cover at Park Vale Comprehensive School with Korst posing as one of the students Carl whilst Kist posed as a science teacher named Tim Jeffrey and Glune posed as the school's head teacher Greg Blakeman. Under the disguise of Carl, Korst went to the school's Science Club run by his father and the only other attendant was a student named Luke Smith who unintentionally told the two Slitheen how to build the final transducer they would use to turn out the Sun. Later Korst tricks two other students Maria Jackson and Clyde Langer into one of the classrooms whilst they were being chased by Kist and reveals himself to be a Slitheen to them and joins up with his father and uncle and pursues them and Luke but Clyde sprays the two with deodorant to give him, Maria and Luke time to get away just as Luke's adoptive mother Sarah Jane arrives just in time to get the three teenagers away much to Korst's anger who wanted to hunt them and is comforted by his father.
Later after the transducer is build Korst pulls the lever to turn off the Sun and then after Sarah Jane and the other return he wishes to hunt them but Glune goes instead saying that a adult better deal with them this time. After Glune is killed by Maria who dowsed him with vinegar (which is harmful to Raxacoicofallapatorians) Korst and his father summon the other Slitheen to the school and when Sarah Jane and Luke arrive, they reveal their plan to them but Luke tells that the machine won't take the power of the Sun and it starts to overload and it is turned off. Luke then uses Sarah Jane's sonic lipstick to cause the machine to malfunction and the room starts to expolde and most of the Slitheen flee leaving Korst and Kist behind who start to follow Sarah Jane and the gang out of the room but they get trapped in the door. Kist begs Sarah Jane to a least save his son but just as Sarah Jane is about to open the door the room explodes. Kist disintegrates and Korst bursts into green light causing the gang to think both Slitheen are dead much to Sarah Jane's sadness as she believes that she allowed a child to die.
The Lost Boy
|“||Revenge at last Luke. I'm going to enjoy this kill. This is for my father||„|
|~ Korst before attempting to attack Luke Smith|
Five months later in February 2009, it is revealed that Korst didn't die along with his father instead he managed to teleport away and plans to get revenge on Sarah Jane and the gang for the deaths of his father and the family that died previously so he aided by two adult Slitheen named Dax and Bloorm joined forces with a crystal-like creature called an Xylok who is also Sarah Jane's computer Mr. Smith. Using improved technology the three Slitheen can now wear the skins of thinner people so Korst takes the disguise of a child prodigy named Nathan Goss and works at an alien technology research centre called the Pharos Institute whilst Dax and Bloorm take the disguise of Jay and Heidi Stafford and claim that Luke is in fact their long lost son Ashley so he is given to them.
Later Korst comes to Dax and Bloorm at the Stafford house and catch Luke trying to escape and reveal themselves to him before taking him to the Pharos Institute to harvest his telekinetic energy. But when they are there Luke overcomes them and escapes with Korst chasing after him into a room which Luke locks him in. Just as Sarah Jane, Maria and her father Alan arrive armed with bottles of vinegar Korst comes back and holds Maria hostage, but lets her go when Sarah Jane and Alan get rid of the vinegar. Korst, Dax and Bloorm then reveal their alliance with Mr. Smith saying that he would help the Slitheen get revenge but are confused on why Mr. Smith sent Sarah Jane to the Pharos Institute then discover that Mr. Smith knew that Luke would escape and return home to him. Korst says he will deal with Mr. Smith later and prepares to kill Sarah Jane but is stopped by Dax who tells him that when he is older he will learn not to make snap decisions and discover that Mr. Smith tricked the Slitheen to power Luke's mind with MITRE in order to destroy Earth by crashing the Moon into it and release his fellow Xylok. Korst plans to escape to his family's ship using his teleporter but Alan takes it off him and gives it to Sarah Jane to get back to her house and with help from her robot dog K9 and puts a virus into Mr. Smith making him forget his's plan and gives it a new purpose to safeguard Earth and sends the Moon back to it's ordinal position. After this Korst along with Dax and Bloorm leave Earth in peace.
- Daddy I want my hunt! (Korst to Kist)
- I'm only twelve
- She must know something, you gravy-brained moron or she wouldn't have been in the lab, would she? (Korst to Dax about Sarah Jane).
- This is my mission. I can talk to him anyway I like (Korst to Bloorm)
- What?, Don't you remember me Luke?. How you killed my family and left me in a sealed room to die?.
- Same Slitheen, different skin. I teleported out and survived. My father wasn't so fortunate. And now, I going to get my revenge.
- I'm Slitheen. You are going to give me my revenge.
- Are you questioning my authority?. You want to trust an Xylok, Dax Fex Fize?. You're as thick as a human.
- You're as slippy as the Bane scum that made you.
- You killed my father, Sarah Jane Smith. At the school? (Korst reminding Sarah Jane who he is)
- Drop your weapons or she dies
- At least I'll be able to tell my family that you're dead Sarah Jane Smith. I'm teleporting back to the ship.
- He is not addressed by his name in the series, only as Carl or Nathan. But his name is revealed as Korst in a novelisation of Revenge of the Slitheen.
- Despite his young age, Korst is quite strong, since he was able to hold Maria by her throat without a problem.
- He is the second member of the Slitheen family to have thought to have died but is revealed to have teleported away from danger in a later episode. The first being Blon Fel-Fotch Passameer-Day Slitheen who was thought to have died in the Doctor Who episode World War Three but was revealed to have escaped in the episode Boom Town.
- He is also the second known Slitheen to have used more than one human disguise. The first was an adult male member who posed as politician Oliver Charles and later General Asquith in the Doctor Who episodes Aliens of London and World War Three.
- Korst is the first of two child Slitheen to appear in the series. The second would be Chris Slitheen who appears in the episode The Gift.
- Korst is similar to Bowser Jr. as both are children and are villains. Both also have fathers who are villains too (Korst with Kist and Bowser Jr. with Bowser) who died. Though in Bowser Jr.'s case, he was able to bring his father back to life whilst Kist is permanently dead.
- It seems that Glun and/or Kist were high-ranking members of the Slitheen family since Korst has authority over Dax and Bloorm despite being younger than them.
- Korst appears to care only about himself as in The Lost Boy when learning the moon was going to crash into Earth, Korst declared "I'm" teleporting back to the ship rather than we. Meaning that he was willing to save himself and leave Dax and Bloorm behind to die along the rest of the life on Earth, despite them being his family.