I am currently listening to Dooku: Jedi Lost, and the mention the Tirra'Taka--especially its brief description--has me very intrigued. And like my theory about Darth Nihilus and the Malachor scenes from the season 2 finale of Rebels, it triggered a new theory which is probably me reaching again. 

Before I explain the theory itself I want to add context by including the quote that made me think of the theory. 

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JENZA: According to legend, the planet was part of the Sith Empire…

DOOKU: The Sith!

JENZA: And my great-great-great-great-something-grandfather led the charge against them.

DOOKU: Your grandfather did? Surely it was the Jedi?

JENZA: Like a Serennian would let someone else take the credit. If you believe the stories—and my father does, passionately—Granddaddy Serenno saw them off single-handedly, and the other houses submitted to his authority.

DOOKU: Renaming the planet in his honor.

JENZA: He formed the council, joined the Republic, and here we are. Although Father’s never been too keen on the last part. DOOKU: Joining the Republic?

JENZA: (PUTTING ON HIS VOICE) “Serenno can look after itself, Jenza!”

DOOKU: (LAUGHS) Well, we know you can. Not many people try to take a bite out of a Karkarodon. It’s usually the other way around.

JENZA: (EMBARRASSED) We should probably get back. We’re not even supposed to be in here. (BEAT) Dooku?

DOOKU: (NARRATION) A carving had caught my attention—an immense beast, larger than any malosaur, crawling up toward the domed ceiling. The creature’s crested head was thrown back, jaw stretched wide, roaring at the stars that were painted across the apex. Spines ridged its powerful back, wings spread wide as if ready to take flight. And then there were its eyes…eyes, though fashioned in stone, that burned with an intensity that was all too familiar…

DOOKU: What is that?

JENZA: The Tirra’Taka? Just another legend. “The dragon that holds the world together…”

DOOKU: It’s beautiful.

DOOKU: (NARRATION) I couldn’t look away, walking toward the sculpture as if in a trance. It looked so alive, so vibrant, as if any minute it could spring from the wall to crash through the columns that held the domed roof in place. I could feel the creature’s heart beating in my own chest, its roar echoing at the back of my mind…

We also hear the roar of the Tirra’Taka. It’s distorted, low, rising in volume beneath the following exchange.

JENZA: Dooku, what are you doing? Don’t—don’t touch it, okay? It’s supposed to be bad luck.

DOOKU: So beautiful.

The ground shakes, dust falling from above.

DOOKU: (NARRATION) I barely even noticed the ground shifting beneath our feet, flakes of paint falling from the ceiling high above…

JENZA: What was that?

DOOKU: (WHISPER) Tirra’Taka…

JENZA: Dooku—don’t!

DOOKU: (NARRATION) My fingers brushed the stone…and the world was torn apart…

A groundquake hits, shaking the foundations of the assembly hall.

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First off, the fact that the ground starts to shake reminds of the scene in Twilight of the Apprentice Part 1 where Ezra touched the pillar of the Sith temple and it starts to glow read underneath his hand. 

Second, the bulk of this theory relies on a scene from the Star Wars Legacy comics issues which were linked to the Vector crossover series. To explain, the panel depicts Karness Muur, a Sith lord alive during the early days of the Sith, observing a massive creature which he has supposedly created using dark side alchemy. 

Linking this to Dooku: Jedi Lost, I feel like the Tirra'Taka's place in Serennian myth, and the assembly hall crumbling as soon as Dooku touches the carving, makes me suspect that the Tirra'Taka may have been a creation of Karness Muur from when the Sith ruled Serenno. The creature was "sedated" somehow (probably by the Jedi, there is no way a bunch of nobles could have beaten something like this), to the point that when a Force wielder touched the carving in the Great Assembly Hall then it would partially awaken. Karness Muur is an awesome character for his brief time in the EU, and I have been wondering for a while about how another character he had a significant history with could fit into the canon. This possibility just makes me think about it even more. 

This is what the line in the story made me think of. Haven't finished it yet but I am enjoying it so far.