I must warn the readers that this chapter contains a bit of body horror.
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He thought often about the first couple of days after the King had drugged him into sleep. When he woke up, he had been already on a small ship for a day and after another whole day on the sea, the ship arrived on Dragonstone. There he had been forced into a Cell and had been given Water and bread and cheese. He tried at first to not eat and drink but after another day his lips were dry and his tongue thick and he gulped down the water and then forced the dried bread and cheese down too.
He was given more Water and even watered Wine the same evening. The next couple of days he was feed thrice a day with thick meat broth and good bread in the mornings, thick Stew and fresh fruit every midday and bread and cheese and boiled eggs every evening. He was given Water and Wine and beer, as much as he wanted every day. The only thing that he was not given was the Chance to clean himself thoroughly or to change his clothing. And he could of course not leave his Cell at all.
Nonetheless, he had thought to himself, the King had clearly given orders to the jailers here on Dragonstone, to treat the captured Lion well enough.
That all changed when the Red Priests arrived on Dragonstone.
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The Stone egg that was laying in his entrails, had started to pulsate some time ago.
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He hated this helplessness even more than the pain.
No that was not true of course. He hated them, those who did this to him, more than anything else but then he hated the pain and then the feeling of helplessness. Yes, that was the correct level and order of his hate.
He felt his breathing became more and more shallow with every hour of agony. Maybe the gods had finally heard his prayers, his half feverish but absolute desperate prayers for death.
His eyes felt so swollen still from his endless crying and his lips felt torn because of dryness and heat. He was so thirsty but no water nor any other drink had been offered to him since they forced him here. He liked to think, whenever he could force himself to think about more than the pain, he liked to think that he wouldn't drink anything anyways, even if they would offer him the sweetest wine or the clearest water. He promised himself that he would not take even one gulp, no he wouldn't because that would have meant that his body would stay alive a bit longer and he wants so desperately to finally die. But it had not mattered anyways because they had not offered him anything at all.
He had tried to ask them why they were doing this to him more than once. He had promised them Gold when they had cut him open, their weight in Gold. He had told them who he was when they tied him down on the Stone, that he was the brother of the Warden of the West. That his family was rich enough to make them drown in Gold if they wished so.
They had not reacted to any of his words and offers. He tried it then in the languages of the Free Cities but they had not reacted to that had only cut him open enough to place the Stone egg into his entrails and then cauterized the cuts. And he had screamed.
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The egg pulsated ever more and more. He felt it pulsate in his belly with the rhythm of his shallow breaths, with his heartbeats, with his thoughts.
He felt it pulsate in his blood and it calmed him so. It sharpened the pain to pure agony again but it also calmed his mind. It promised him vengeance, pure hateful vengeance and that made him happy enough to accept the ever more doubling of the searing agony in his body.
He felt his entrails cooking and fire running through his body. It had cracked open but not top for all to see, no it had cracked open on the deepest part, buried in his entrails and blood. He felt something even deeper inside of him.
He wanted to scream because nothing, even the sweet and numbing promise of of hateful revenge, was enough anymore to endure the uncontrollable pain but he felt something sliding up his throat and keeping him silent. It tore through the inner walls of his throat and swallowed his screams at same time.
He still was alive but barely, when it then slid even higher, up from his throat and into his mouth where it ripped away his tongue and he felt the blood running everywhere. Then this something forced itself even higher, up into his nose and then, finally then, he stopped feeling.
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Four Red clothed priests of R'hllor came running when they no longer heard the screams of the first offering but instead gurgling sounds. They arrived in front of the bound young captive in the same moment when the head of said goldenhaired captive bursts open.
It was not a dragon that escaped the head but a far older Creature. Only one of the priests escaped death long enough, even though he escaped with horrible wounds from this far down in the Dragonstone's deep caverns and lived long enough to tell that the King should know that it was not a Dragon in that Egg but a Firewyrm.
Then the last of the Red Priests died too.
And the Firewyrm feasted on the flesh of the three priests and the one Lion whose blood had nourished him, down below in the deepest Caverns of Dragonstone.
The King's loyal men high up in the Dragon's Castle looked at each other. Their young King will not like this news.
Not a Dragon but a Firewyrm.
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The continuity of the use of 'He' is wanted for this chapter. Gerion lost himself in his thoughts here and this is how that sounds.
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Firewyrm emotions
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Warmth. Home. Birth. Blood.
...Sweet blood. Live. Other warmth. Not in shell but soft now.
... . Blood smells like gold.
Livegiver. Smells like cold and hot. No, smells thoughts of hot and cold and Hate.
Hate smells good. Smells like pain. Sweet Blood Lifegiver. Hate taste good. Sweet Blood of Hate.
...Pain tastes good. Lifegiver tastes sweet and good. Lifegiver heart, no more beat. Blood so sweet.
Others here. More beats. Smells like Fire. Not Fire. Other Fire. Bad Fire. Danger. Enemy. ...
Tastes Blood. Bad Fire Blood. Bad Enemy. Bad Blood. Bad meat. Sates but bad Taste...
Lifegiver good taste. Sweet of Hate and Pain and Lion thoughts and Gold thoughts. ...
Enemies bad taste. Old. Sour. Only good to eat but not liking it...
Lifegiver sweet. Liking it ... More... Want more... Enemies too. Want Kill. Want Blood. Sweet and Sour. Good and Bad. Lifegiver and Enemy. Want Blood. Want Meat. Want More...
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Copied from ASOIAF Wiki
Firewyrms are creatures that breathe fire but have no wings, and are possibly related to dragons. They can bore through rock, soil, and stone.[1][2] According to old tales, firewyrms were in the Fourteen Flames of the Valyrian peninsula even before the dragons came. Their young are not much bigger than a child's arm, but as they age they can grow to immense sizes. They have no love for men.[1]
Firewyrms were encountered by slaves of the Valyrian Freehold in the mines of the Fourteen Flames. Burnt and blackened corpses were often found in shafts where the rocks were cracked or full of holes