Episode still, AI enhanced
The ThunderCat who went bad
Grune the Destroyer
A ThunderCat, with all the skills that go with the title
He was Jaga friend. They defended Thundera side by side. Then greed took him, and the ThunderCats got the one enemy they were never trained to fight: one of their own.
The Record
Grune at a glance
Pick Your Grune
Two ULTIMATES, both in stock
Super7 has made Grune twice at 7 inch scale. One matches the cartoon, one matches the old toy. Both carry a $55 MSRP and both are discounted at BigBadToyStore right now.
ULTIMATES! Grune the Destroyer
Wave 2, cartoon colours. Tan chest, blue trunks and boots, silver shoulder armour, purple Seal of Grune.
- Club and brass knuckles
- Seal of Grune, plus a broken Seal
- Broken Sword of Omens
- Alternate armour with ThunderCats logo
- Alternate head and interchangeable hands
ULTIMATES! Grune the Destroyer (Toy Recolor)
Wave 9, vintage toy colours. Silver chest, red trunks, red headband, silver boots, taken off the old card art.
- Club and brass knuckles
- Two interchangeable head designs
- Interchangeable hands
- Vintage toy inspired paint detail
Prices and stock checked 29 July 2026. In collaboration with BigBadToyStore. #BBTSpartner
The one you cannot get. Super7 also made a Ghost Grune in translucent plastic, with the Sword of Omens, a broken Seal of Grune and a club moulded to match. It is retired and BigBadToyStore does not stock it, so the aftermarket is the only route. See the archive entry.
The Betrayal
He carried the mantle, then dropped it
Grune is every Thunderian worst nightmare. Not an outsider, not a mutant, not an ancient evil dug out of a pyramid. A ThunderCat, with every enhanced skill the title carries, and a lust for power that hollowed him out from the inside.
That is what makes him land. The Code of Thundera, justice, truth, honour, loyalty, is not a slogan on a wall for these characters. It is the structure their lives are built on. To turn your back on it is to shed part of yourself. Grune did it anyway, and Cheetara vision of his followers massed behind him shows he was not alone in doing it.
Panthro puts it plainest when the ThunderCats work out what they are facing: a ThunderCat gone bad.
He was one of them. In Cheetara vision of Thundera, Grune still wears the ThunderCats insignia on his chest. The show gives you the image of him as a hero before it asks you to watch him become the thing Jaga has to destroy.
On Screen
The Ghost Warrior
Written by Leonard Starr, directed by Arthur Rankin Jr., first aired September 20, 1985. Arguably the darkest thing the 1985 series ever did, and one of the best written.
Two Bolkins go looking for valuables in an abandoned tomb and break a seal they should have left alone. What comes out is a ghost with a grudge. Grune drains Cats Lair of its Thundrillium, levels a Wollo village, and hammers himself a club out of a Thundrainium fire rock, the one substance that can bring a ThunderCat down.
Jaga comes to face him, and the two giant spirits fight in the sky above Cats Lair. It is one of the most striking images in the whole series, and one of the only times the other ThunderCats see Jaga in spirit form at all. Weakened by the Thundrainium, Jaga starts to lose. Lion-O throws his own strength into Jaga failing form and sends him the Sword of Omens, and with that power Jaga blasts Grune into nothingness, then returns the Sword just in time to save Lion-O life.
An animation detail worth catching. Jaga usually appears in a blue and grey palette to signal that he is a ghost. In this episode the animators give him his original Exodus colours instead, the same treatment he gets later in The Astral Prison.
Stills captured from ThunderCats, The Ghost Warrior (1985). Copyright WBEI.
The Other First
Cheetara sixth sense starts here
Grune is not the only thing this episode introduces. Cheetara had already carried episodes like Trouble With Time and Pumm-Ra as a character who could handle herself. Here the writers hand her something else: a sixth sense that is an asset and a liability at once, a gift that costs her something to use.
Ordinary visions come to her throughout the rest of the series. The self induced trance, the version that visibly takes a toll, comes back only once, in ThunderCats Ho! Part One. Both of Grune major returns and both of Cheetara trances sit in the same small handful of episodes, which is not a coincidence. He is the threat she has to reach into the past to understand.
The Other Two
He does not stay gone
Being blasted into nothingness turns out to be survivable if you are Grune. He returns twice more in the 1985 series.
ThunderCats Ho! Part V brings him back for the five part epic, again written by Leonard Starr, first aired September 14, 1987. Return to Thundera Part II, written by Peter Lawrence and first aired September 5, 1989, gives him his last outing in the original run.
The 2011 series does something different with him again, recasting Grune as Panthro former comrade in arms and giving the betrayal a personal weight the 1985 version leaves implied. If you only know him from The Ghost Warrior, the 2011 arc is worth the time.
Sixty Seconds
The short version
Grune on Thundera, and the two figures you can put on a shelf.
Forty Years of Grune
Every figure in the archive
The Long Grudge
Grune, decade by decade
The Ghost Warrior
Grune debuts, and Cheetara sixth sense debuts with him. First aired September 20, 1985.
LJN puts him on a card
The vintage figure arrives, in the silver and red deco Super7 would revive nearly forty years later.
ThunderCats Ho!
He returns for Part V of the five part epic, again written by Leonard Starr.
Return to Thundera Part II
His final appearance in the original run, written by Peter Lawrence.
Panthro old comrade
The 2011 series recasts Grune as a former brother in arms, making the betrayal personal.
ULTIMATES Wave 2
Super7 gives him the cartoon accurate treatment at 7 inch scale.
Toy colours, and a ghost
Wave 9 revives the vintage deco, and a translucent Ghost Grune arrives alongside it.
Questions
Everything fans are asking
Who is Grune the Destroyer?
Grune was a ThunderCat. He served as a general of the Thunderian army and fought beside Jaga defending Thundera, until a lust for power turned him against his own people. He is the series answer to a question the ThunderCats never otherwise have to face: what happens when one of them breaks the Code of Thundera.
Which episodes is Grune in?
Three in the 1985 series. The Ghost Warrior, which introduces him, then ThunderCats Ho! Part V, and Return to Thundera Part II. He is also a major character in the 2011 series, where he is reimagined as Panthro former comrade.
How was Grune released from his tomb?
Two Bolkins, the small sheep faced Third Earth race that this episode introduces, broke into an abandoned tomb looking for valuables and accidentally freed his ghost.
What is Grune weapon?
A club forged from Thundrainium, the substance that weakens ThunderCats. He hammers it out of a fire rock after draining Cats Lair of its Thundrillium power source and destroying a Wollo village.
Why does Thundrainium not affect Grune?
The series never explains it. He is a Thunderian and a former ThunderCat, so it should weaken him. If the answer is that his ghost form protects him, that raises the obvious follow up question of why Thundrainium so clearly does weaken Jaga, who is also a spirit.
How is Grune defeated?
Jaga fights him and is losing, weakened by the Thundrainium club. Lion-O risks his own life to project his strength into Jaga failing form and throws him the Sword of Omens. With that power Jaga blasts Grune into nothingness, then returns the Sword to Lion-O in time to save him.
Is The Ghost Warrior the episode where Cheetara sixth sense debuts?
Yes. This is the first appearance of her sixth sense, and of the self induced trance in particular. The trance version returns only once more, in ThunderCats Ho! Part One, though ordinary visions come to her throughout the series.
Which Grune action figures can I actually buy right now?
Two Super7 ULTIMATES figures are in stock: the Wave 2 Grune in his cartoon colours, and the Wave 9 Grune in vintage toy colours. Both are 7 inch, both carry a $55 MSRP, and both are discounted at BigBadToyStore at the time of writing. The translucent Ghost Grune ULTIMATES is retired and no longer stocked there.
What is the difference between the two ULTIMATES Grune figures?
Deco, almost entirely. The Wave 2 figure matches how Grune appears on screen: tan chest, blue trunks and boots, silver shoulder armour, and the purple Seal of Grune. The Wave 9 Toy Recolor copies the vintage LJN toy instead, with a silver chest, red trunks, a red headband and silver boots. The accessory loadouts differ too, with the Wave 2 figure carrying the larger assortment.
Episode details, synopsis and review drawn from the thundercats.org episode guide and encyclopedia. Stills captured from the 1985 series. Product photography courtesy of Super7 and BigBadToyStore. The hero image is a still from The Ghost Warrior, AI enhanced for resolution.
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