Brimstone debuted in the episode What Lies Beneath, where he was seen on his throne in the Deep Caverns and introduced himself as the High Commander of the Darkbane. He would then go on to saying that they (Shane Gang) aren't the first midlanders to enter the Deep Caverns, and that he has dealt with Humans before, including The Shanes. In What Lies Beneath, Brimstone intended to break through the Guardian Gate force field and lead his army into SlugTerra, however they would fail but he promised that him and the Shane (Eli) would meet again.
Brimstone's later seen in a flashback in Back to Blakk, where Blakk is seen making a deal with him and the Darkbane, where they would supply Blakk with Dark Water and in exchange Blakk would have to allow one of the Darkbane to disguise themselves and return to Slugterra with him.
- He can throw lava out of his hands like the other Darkbane.
- He is strong enough to grab or hit a slug that has hit velocity with his bare hands.
- What Lies Beneath (First appearance)
- The Return (Mentioned only)
- It Comes by Night (Appears in flashback(s))
- Back to Blakk (Appears in flashback(s))
- Dark as Night (Eli's review of Dr. Blakk's plans)
- Light as Day
- Slugterra: Ghoul from Beyond (Appears in flashback(s))
- Brimstone bears several similarites to the Devil from Christian lore: both are horned demons trapped in the center of the earth, they are both assciated with fire and lava, they both seek to conquer the surface world the list goes on.
- He never stops trying to find a way to Slugterra from the Deep Caverns.
- He has made some kind of deal with Dr. Blakk, which was to let a Darkbane follow him to Slugterra. (El Diablos Nacho).
- He has dealt with people from Slugterra before, he refers to the people of Slugterra as mid-landers.
- His throne has the symbol of the sun.
- He knows about The Surface and is trying to conquer it.
- He has dealt with a Shane besides Eli Shane before, probably Will Shane.