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Dr. Thaddius Blakk is the main antagonist of Slugterra, and the owner of Blakk Industries.


The owner of the powerful Blakk Industries, Dr. Blakk's business dealings have made him a rich and powerful man. Ultimately, his business is hiding his true purpose: to control all of Slugterra and destroy the magical slug energy that protects this underground world. A powerful slugslinger with a terrifying multi-shot Harbinger Firestorm blaster, Blakk has corrupted his slugs through the dark science of ghouling, turning them into ruthless shadows of their former sluggy selves.

Powers and abilities

  • Blakk is a genius inventor who has enough mechanical knowledge to make gattlers, terraportals, flying trains and enough chemichal knowledge to create ghoul slugs.
  • Blakk is a skilled slugslinger who could compete with Will Shane himself (even if he couldn't defeat him without using ghouls). Although he never had exceptional talent like the Shane family, he made up for it with innovative tendencies. At one point, he was considered worthy to become the student of the Unbeatable Master herself.
  • He has enough strength in his normal form to take down an arachnet at full velocity by punching it.
  • In his monster form, he gained the ability to ghoul slugs without the use of machines. He can also strike down Eli's megamorph rammstone with seemingly little effort.


Thaddius Blakk grew up dreaming of becoming the top Slugslinger around. He was also a candidate for becoming a student of the Unbeatable Master, but he lost to Will Shane. He would do anything to win, even cheat. This didn't sit well with Will Shane, who was his top rival. After he defeated Will Shane, Blakk retired from Slugslinging uncontested and turned his interests to science and industry. Blakk took a broken-down train system and turned it into the SlugTerran Express, a system of high-tech, high-speed trains that connect all but the most remote caverns. Despite his success and wealth, Blakk remained unsatisfied. For he will settle for nothing less than total domination of all SlugTerra.

In "Back to Blakk" he reveals his life's story, to Eli and Burpy, beginning with when his father abandoned him, causing Blakk to grow up in a lawless cavern. After his encounter with the Unbeatable Master, he returned to take the cavern for his own. This lead to his first encounter with Will Shane, as well as Blakk's discovery of dark water. After some experiments, he was taken to the Deep Caverns, causing his skin to become white and leading to his alliance with the Darkbane. As shown in "Back to Blakk", his first ghoul was a Greneater. Following those events, Blakk used a Tempesto to defeat Will Shane. After his henchmen failed to free him, Blakk managed to escape with the help of Nacho and four other Darkbane.

Meanwhile, Blakk continued to transform Slugs in Ghouls to free all Darkbane and conquer all of Slugterra and the Surface.

In "Light as Day" he fights his final battle against the Shane Gang, along with Locke and Lode, Nacho and four others Darkbane. While his allies are all defeated, Blakk didn't loose his composure, as his portal opened and Brimstone and all the others Darkbane began to arrive en masse to fight the Shane Gang and the Shadow Clan. But Eli used Doc (given to Pronto by the Shadow Clan) to cure all of Blakk's Ghouls back into Slugs, causing the portal to suck Brimstone and all others Darkbane back into Deep Caverns. Defeated, Blakk tried to escape, but the Shadow Clan Leader and Eli stopped him. Although he pushed Eli into the portal, Eli fired Burpy to also send Blakk in the portal. He tried to take Eli in his fall but Joules, Banger, Chiller and Spinner disposed of Blakk and Burpy saved them all before the portal was closed by the Shadow Clan Leader.

Slugterra: Return of the Elementals

After being sucked in the Terraportal to the Deep Caverns, Blakk returned as the secondary antagonist in Return of the Elementals in a mutated form. He worked with the Goon (and later controlled by it) to capture and ghoul all the Elemental Slugs, but failed and was trapped along with the Goon in the Deep Caverns by Will Shane.

Family Tree

Harlan E. Blakk
Thaddius Blakk
Thaddius D. Blakk


  • Blakk has only beaten Will Shane in a duel once. However, Season 1 gives us two different flashbacks, so it's unclear how exactly the duel went on.
  • Blakk can carry a Gattler while others have to mount it onto a cart, hinting that he is pretty strong.
  • Blakk fears Fusion Shots, as seen in "The Return".
  • Although he fears fusion shots, it is seen in "The Unbeatable Master" that even they do limited damage to Blakk.
  • The 'V'-shaped insignia that Blakk wears originally came from Viggo Dare, as a symbol worn by his gang members.
  • Blakk's skin was originally tan (as an adult) but turned pale due to an unstable Deep Cavern portal.
  • In The World Beneath Our Feet Part 1, we can see a Flopper in Blakk's bandoleer.
  • In his new form, his left hand has four fingers.
  • After his trip to The Deep Caverns, Blakk turned into a more monstrous form, similar to The Emperor after he fell into Dark Water.
  • In his new form, he can ghoul slugs without the need of machines - again, just like The Emperor after falling into Dark Water.
  • In Back to Blakk, he appears interested in the Shanes' secret about the Burning World, as if he suspected that it is more than a legend, but Eli refuses to reveal his secret. However, in Into the Shadows, his son Tad comes to Slugterra from the Surface and already knows about his father's enterprise and Ghouling. As such, Blakk's knowledge about Surface is still unclear.


See: Dr. Blakk/Gallery

Slugslingers in SlugTerra
Heroes Will Shane · Eli Shane · Beatrice Sting · Kord Zane · Pronto · Jimmo Shane · Junjie · Yang
Villains Dr. Blakk · Viggo Dare · Nacho · Twist · Mr. Saturday · Blite · Malvolio Drake · Brutale Drake · John Bull · C.C. · Billy · Shorty · Glasses · Boss Ember · Straggus · Mongo · Locke and Lode · Sedo · Sergeant Slug · Blakk Employees · Quentin · Maurice · The Game Master · Dark Servants · Spirex · The Emperor · Dai-Fu · Jonny Man · Tad
Recurring Gerhard Stocker · The Gentleman · Mario Bravado · Dana Por · Shockwire · King of Sling · Marcus · Gabe · Fav · Frost · Jacques · Waylon · Munch · Flame · Millard Milford · Swick · Drucilla · Underlord Sleade
Other Shanai · Tom Por · Turtleton