With the Dornishmen scattered across Dorne, Aerion's direct and swift arrival to Sunspear was met with little resistance. He permanently docked three ships at Sunspear, sending the rest to occupy every other coastal settlement in Dorne. That said, he sat at the seat of Sunspear with a little over three hundred living men. Within a week, he declared himself the new castellan and Warden of the Sands... waiting for the resistance to emerge.
In time, they did.
...
Aerion's men were pushed back to the Tower of the Sun's hall, where Aerion comfortably sat on one of the two seats. The seats were almost identical, with one being inlaid with the Martell spear and the other with the sun that flew from the masts of Nymeria's ships long ago. Aerion took the seat of the spear, which the ruling Prince of Dorne would.
Aerion's men faltered under the relentless wave of Dornish spears, dropping their weapons while Aerion remained calm. In turn, they were ruthlessly slaughtered.
"Greetings, my dear Martells."
"You sit atop that seat like it is yours." Nymor Martell, the aged son of Meria Martell, frowned. "Do not fret, you will be joining Lord Rosby soon enough."
"How unpleasant... you wish to throw me through a window. I feel heartbroken. Truly."
Aerion stood up from his seat and descended down. Within seconds, he was encircled by Dornish spears and faced with the rather fierce gaze of both Nymor Martell and his daughter. Aerion, however, was rather unworried... for good reason.
People did not call him a God just because he was beautiful.
"It is true what they say, Dornish women do age like fine wine. Even when you're forty, you look so... alluring. Mayhaps I'll have to play out the Dornishman's Wife. Except... your man wouldn't beat me in a duel, would he?"
Aerion exchanged a glance with Deria Martell, winking rather charmingly. She did not take it too well, however.
"Seize this bumbling fool."
"So heartful."
Aerion opened his palm and every spear near his vicinity turned to flame, burning away completely like they never existed. This shocked the Dornishmen, causing them to look at Aerion with befuddled and frightened expressions. If he could burn through iron spear points... what could he do to a man? They certainly did not want to find out.
"When I sent away thirty thousand men from the seat of Dorne, do you believe that it was in jest? Perhaps you thought me for a mad fool... but my true intent was to see you all show yourselves. That much you did."
"... What are you? Why do you fight for Aegon when you wield such power of your own?"
"I'll tell you over a few goblets of Dornish red." Aerion offered with a smile. "There's no need to lose any more Dornishmen in this conflict, I assure you. This war is good for no one, least of all Dorne."
~
Aerion sat down with the Martells and had some diplomatic talks. Without utilising magic, Aerion convinced the Martells to stand down with words alone. A few compromises were made, certainly, such as Martells being able to still style themselves as princes and princesses... but they were quite agreeable on both sides. Now, Aerion only had to bring those terms to King Aegon himself.
So... he did.
"No, I object. Such an agreement would show weakness." Aegon threw it into the fire.
"..." Aerion raised an eyebrow. "Your dragons burning abandoned castles to no effect does not show much strength either. You know what... I'll give you something to read."
"And that will be useful how?"
"More than you think."
Aerion finally gave Aegon all of his written books leading from the Dance of the Dragons all the way to the Tourney of Harrenhal. Meanwhile, Aerion himself returned to Harrenhal and, through the Crown of Necromancy, instructed his fleet to return to Lys. Before long, it was King Aegon who came to him.
...
"Do you believe what I wrote?" Aerion wondered.
"... Is it the truth?" Aegon replied, looking into Aerion's eyes. "I had thought that my dynasty would last well over a thousand years and yet, according to what you wrote, it almost broke itself in less than three hundred years. No dragons... means nothing truly keeping the lords from rebelling. One inept king and it all ends."
"Quite right. My grandsire was that 'terrible' king who threw your great dynasty into the mud." Aerion nodded. "By the age of three, the pressuring weight of your dynasty laid on my little shoulders. When most of the Realm wished me dead, do you know which kingdom out of all the Seven kept me safe? It was Dorne, the most loyal of all."
"... What happened next? How did you find yourself in the past?" A rather intrigued Aegon inquired.
"Ah, that's the final book." Aerion chuckled. "The Rise and Reign. I took the most pleasure in writing this one, of course... you can read it right now if you want."
"Where is it?"
"Right here."
Aerion stood up and took out one of the books from his shelf, presenting it before Aegon. He went on to read all of it... this time with Aerion for company. He answered all of his questions and remarks, from which the air of 'mystery' and tension between the two vanished. For further evidence, Aerion's banner and necklace were for show. Realising that he was his successor, Aegon began to express pride in Aerion's accomplishments.
"... I can't believe it." Aegon laughed. "All along, you were right there. My successor."
"Keep it a secret, alright?" Aerion looked into Aegon's eyes. "This was my gift to you and to you alone."
"As you wish. But... how was I remembered?"
"Aegon the Conqueror," Aerion replied. "The formidable conqueror who weaved the first strings to put the Realm into place as one. But..."
"But?"
"You are remembered as the Conqueror... but not that great of a king. There were several others who ruled better. Some far better, even"
"... I see." Aegon nodded. "It is no secret that I do not rule day-to-day."
"So will you accept Dorne's terms now?"
"Do you even need to ask? I will not risk the life of Rhaenys for a futile conquest... nor will I burn the lands that are so precious to you. It would be rather suicidal of me to continue refusing your advice, I'd think."
"I wouldn't harm you, my great great great great great... it goes on for quite a while. I shall call you my ancestor instead." Aerion laughed. "Now, hurting the elderly is frowned upon, is it not?"
"I am not quite so old yet." Aegon shook his head, smiling slightly. "Out of all the future kings you told me about, the one I admire most happens to stand right before me. You rose from almost nothing at all... to having most of the known world bend beneath you. I'd have loved to see your world for myself as you see mine."
"Oh, I can show you to my world after you die... I think." Aerion chuckled. "You could meet Viserys and his little golden children, Jon, Dany, my slightly grumpy Daemon and lovely Nymeria."
"Grumpy Daemon... what did the poor child do to earn such a nickname?" Aegon chuckled.
"By being wilful... ah, he'll be rather troublesome when he matures, I know it." Aerion sighed. "As much as I love seeing the past, it is the present where those who are important to me live. For my son... I want to be there for him as my father couldn't be there for me. The same for Nymeria."
"You are a dutiful man." Aegon nodded in an agreeable manner. "To both your family and your Realm."
"Would you join my council when you're ready?" Aerion offered. "No matter what you do, the past will not ever change... only the present. You could spend so many more years beside your beloved and see much more of the world."
"... That's a rather sudden proposition," Aegon replied as he stroked his chin. "I will consider it."
"Good." Aerion smiled. "I'd love to have you aboard. There are plenty more lands outside of the known world to be conquered, I'm sure of it."
"You won't stop until the entire world is yours, will you?"
"I might leave some of the conquering to my sons." Aerion shrugged. "Give them something to do."
"If ambition was a man, he would be you," Aegon remarked, taking up a goblet of Dornish red and raising it. "To the Holy Valyrian Emperor."
Aerion took up his goblet too.
"To Aegon the Conqueror, my great ancestor."
"Ah... it has a rather sweet taste to it, I'll admit. I think I'm starting to like it." Aegon stated, putting down the goblet.
"We'll make a Dornishman out of you yet." Aerion chuckled.