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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.


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 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. Now, 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", the first ghoul was a Greneater. Following those events, Blakk used a Tempesto to defeat Will Shane. After his henchmen failed to free him, Blakk succeeds to escape with Nacho's help and four others Darkbane.

He continues to transform Slugs in Ghouls to free all Darkbane and conquer all Slugterra.

In "Light as Day" he fights in his final battle against the Shane Gang, with Locke and Lode, Nacho and four others Darkbane. While his allies are all defeated, Blakk is completely confident because his portal open and Brimstone and the others Darkbane begin to arrive to fight the Shane Gang and the Shadow Clan. But Eli uses Doc (given to Pronto by the Shadow Clan) to cure all Ghouls in Slugs, and the portal aspire Brimstone and all others Darkbane. Blakk tries to flee but the Shadow Clan Leader and Eli stop him. He pushes Eli into the portal but Eli sends Burpy who sent Blakk in the portal. He tries to take Eli in his fall but Joules, Banger, Chiller and Spinner dispose of Blakk and Burpy saves them all, before the portal closes by the Shadow Clan Leader.

Slugterra: Return of the Elementals

After being sucked in a terraportal to the Deep Caverns. He returned as the secondary antagonist in Return of the Elementals in a mutated form and he is working with the Goon and later controlled by the Goon to capture and ghoul the Elemental Slugs, but failed and along with the Goon was trapped in the Deep Caverns by Will Shane.

Family Tree

Harlan E. Blakk
Thaddius Blakk
Thaddius D. Blakk


  • Blakk only beat Will Shane in a duel once.
  • Blakk can carry a Gattler while others have to mount it onto a cart, hinting that he is strong.
  • Blakk fears a Fusion Shot, as seen in "The Return".
  • Although he fears fusion shots it is seen in "The Unbeatable Master" that even they do limited damage to him.
  • The 'V'-shaped insignia that Blakk wears originally came from Viggo Dare, 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, he turned into a monster, similar to after The Emperor fell into Dark Water.
  • In his new form, he can ghoul slugs, without the need of machines, 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. So 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