Skyreach and Starfall fell soon after Hellholt had fallen. And much like with the Uller's heir, more from Starfall and Skyreach had surrendered their blades and bent the knee to Aegon the Dragon. Of course, nobody saw this in the best of lights. Dorne had always been known for their cunning and strategies more than their might on the battlefield. Everybody saw a plot beneath their surrender, where perhaps they stab Aegon's armies from behind and defeat them from the inside.
But the Targaryen siblings did not see this plot, or even if they saw it ignored it completely. They accepted the surrender with open arms and toasted their newfound friendship before adding the prisoners to the Dornish ally forces, to use secret pathways to infiltrate enemy castles and dismantle them from the inside.
And so far the plans worked in the Targaryen's favour. The Dornish allies did their work without question. And as more castles fell to the Targaryens, soon the other Lords forgot their suspicions.
The Targaryen host reunited at Vaith after Aenar and Visenya's forces had taken it, before breaking off into two groups once more, this time Aenar and Rhaenys joining forces while Visenya and Aegon joined forces. Aenar, Rhaenys and the Stormlands host led by Orys Baratheon marched for the Tor (an allied castle that welcomed them) while Aegon, Rhaenyra and the host of Rach forces led by Harlan Tyrell marched for the Salt Shore (another allied castle).
Lords Allyrion, Blackmont, Jordayne and Manwoody went with Aenar and Rhaenys' forces, while Lords Gargalen, Qorgyle, Wyl and Yronwood went with Aedon and Visneya's forces. The prisoners turned allies were divided amongst the hosts as equally as possible.
Ghost Hill and Lemonwood soon fell to the Targaryen armies, but this time there were no men who surrendered themselves. Both sides endured heavy casualties before both castles met the same end as that of the others that opposed the Targaryens, melted beyond repair and the surrounding sands turned to glass.
Finally, both forces marched to Sunspear. The remaining Dornish troops allied to the Crown used the tunnels like before, but unlike before the Targaryen troops did not wait for any signals. The dragons flew at the same time as the Dornish troops. Taking down one dragon with a Scorpion was easy, taking down four was not, regardless of how many of those contraptions were set up. Dragons were faster in the air, and when one aimed at a Dragon, another would come behind it and shatter it with its flames. When two aimed at two dragons, a third would fly in and destroy them both.
Sunspear had only two towers that were high enough to install a Scorpion on that could effectively shoot down a Dragon flying high, while the walls around the settlement were not so high that any Scorpion shot from there would hit a target that flew so high that they were mere specks in the sky. Because the Targaryens flew high and only dived down when they would attack.
Towers and walls melted and twisted under the assault of four fully-grown dragons, gates burned to ashes, and people ran but could not find a place to shelter themselves. And just as everything around the main castle burned, the Dragons pulled back. When things cooled enough, the Targaryen army swarmed the grounds. They killed anyone that survived, cut down anyone that tried to stop them and made sure nobody escaped.
Inside the Castle, the allied Dornish troops took down the Martell forces and opened its gates for the Targaryen army.
Sunspear was captured and reduced to nothing but a melted and twisted castle.
Anything on the upper levels of the Castle was deemed a hazard, so everyone gathered on the lower floors, mainly the Great Hall. Aegon, Rhaenys and Visenya sat at the head of the room, while Orys, Aenar, Harlan, Yorick and other Reach, Stormlands and Dornish Lords sat a level or two below them. They were all in good spirits, having successfully dominated all of Dorne's rebels and conquered it in Aegon's name. It took them over a year (almost two) but they had done it.
Lord Yorick Yronwood was named the Warden of The Sands, something all gathered men (Dornish or not) agreed to full-heartedly. Even the once enemies had become friends.
After a while, the Targaryen siblings broke away from the group. They went below the lower levels of the castle, to the dungeons where the prisoners were held.
The Martells welcomed the Targaryens bound in chains and dressed in dirtied finery.
"Lord Aenar" the Yellow Toad croaked.
"Princess Meria" Aenar nodded, before greeting her son Nymor and daughter Deria in the same manner. "My brother, King Aegon, First of His Name, King of the Andals, the Rhoynar, and the First Men. Lord of the Seven Kingdoms. My sisters, Queen Visenya and Queen Rhaenys."
"King of the Rhoynar" Deria Martell snorted, "where are the Rhoynar that you lord over? Dead!"
"And whose fault is that?" Aegon asked simply, "We gave you the option. We gave you two in fact. Neither appealed to you."
"We do not bend, we do not bow, we do not break" Deria sneered.
"No, only end up in chains" Rhaenys drawled.
"Your plot was not a bad one, I will admit" Visenya spoke, "have some of your lords submit to us so when we least expect it they turn on us. But you simply underestimated how much they dislike you and wished for a better leader."
Surprise flickered over Nymor Martell's features and Visenya laughed.
"Not much escapes my eyes, Prince."
"Lord Yorick Yronwood will be the Warden of The Sands, the Crown's representative on Dorne. Starfall, Skyreach, Hellholt, Vaith, Lemonwood, Ghost Hill and Sunspear will all be burned till there remains nothing of them. Their people will be divided among those that were loyal to me. Any Lords or their children will be stripped of their titles and be given to the Lords that they end up with. They will decide what to do with them."
"Why are you telling us this?" Meria Martell questioned.
"So you know what your stubbornness has done to your people. You put your pride over the safety of your people, and now they all face judgment for being loyal to you" Aegon lifted his chin. "You have failed as a leader, Princess."
Princess Meria spat.
"What will happen to us?" Nymor asked.
"Death by fire" Aenar answered with a shrug, "the same manner in which your loyalist Lords died. It would only be fair."
"We shall die as we lived then, unbent, unbowed, unbroken" Deria stated calmly.
"I do not know about unbent and unbroken when you get dowsed by dragon fire" Rhaenys smirked.
Meria Martell snorted and gained all attention again.
"Well if we are to die, might as well congratulate you, Lord Aenar."
Aenar looked at her with confusion.
"I am told your wife birthed a beautiful baby boy. Your hair but his mother's eyes."
Tension seeped into Aenar.
Meria smiled at the expression.
"Oh, you did not know. A shame then."
The old woman yelped when Aenar grabbed her by the head and stared her in the eyes.
"What did you do" he demanded to know, his voice oddly echoing more than what was normal under the castle. But nobody seemed to notice. Visenya, Aegon and Rhaenys were equally shocked, while Nymor had his head lowered. Only Deria and Meria were smiling.
"You should leave now. Mayhaps you'll get to see him one last time."
Meria Martell laughed… Then she stopped suddenly and choked. Aenar was pressing down on his head and pain flared down her spine. The last thing she saw were malevolent red eyes staring at her.
Nymor and Deria on the other hand saw different things. They watched the Princess of Dorne croak before with a sickening crunch her neck shattered. Her head was pushed down and kept going down until her form did not resemble that of a human's at all, her innards squished and spread all around her. Blood splattered on them both and on Aenar, who was still grasping the woman's head.
"Wha- what are you?!" Nymor shouted.
Meria Martell's skull smashed under Aenar's grip and he looked up. Instantly Nymor began screaming as he erupted with flames from the inside.
Deria tried to scramble back but she began choking. Her face turned blue as if she was being choked before she fell to the side, drool falling from her gaping dead mouth.
The Targaryen siblings watched it all with stunned silence and horror. But before they could say anything, Aenar had rushed out of the cell, his footsteps echoing through the underground prison.
I am sticking with canon loosely here in terms of the Dornish wars. It all began from 4 AC and by 6 AC it became a blood bath. In this story in 6 AC Dorne was conquered.
So by that logic, Aenar's son was born sometime late 5 AC.