i) Elia
It had started with a sign from the Gods.
The Poison is procured easily enough, Maester Pycelle never having enough sense to keep an eye on his stocks.
A sign that another family had been chosen in the Targaryen's place.
He pours it into the glass himself, though subtly enough that a servant could be blamed in his place.
He didn't know why he hadn't seen it before, the fates must have been screaming at his ignorance!
One tear falls in also, for the life that might have been.
But how to ensure they inherited the throne? His father, his family, the Kingdom would never stand for it!
He doesn't take the glass over himself, content that his prediction will ensure the child is never born.
They must die.
Elia drinks the moontea without a single suspicion of its existence.
We must die.
The thing that might have been a child is revealed in a cascade of blood and tears.
A Song of Ice and Fire.
Five Dragons breathe upon the Dawn.
ii) Aerys
Rhaegar had expected to feel more regretful as he snuck through the tunnels of the Red Keep. This is perhaps the most dangerous part of his plan, a single misstep here will end with him executed for regicide and Viserys as King.
Part of him even wishes for it, a reprise from the prospect of executing his family. They wear dragons, rode dragons, are dragons - why are the Baratheons the ones chosen by fate? Is it that his family has lost their way? Is it that they've become to Westerosised? Is it because they've lost their dragons?
Is the prophecy wrong?
A Song of Ice and Fire...
No. No, the prophecy couldn't be wrong. No! He was a fool to even question that, the words had been passed down through the centuries for him for understand - that was obvious. He was the harbinger of a new age, not the creator - the Targaryens were unworthy. He was unworthy.
He resumed his progress towards his father's rooms. The court believed that he and Jon Connington were currently out on a hunting trip. Jon had certainly believed that - indeed he had been quite excited at the idea - until Rhaegar's blade had plunged into his throat. Jon's body would never be found, Rhaegar himself will return in two days claiming an attack by bandits.
None will suspect him of Kinslaying, none...
"What are you doing boy?!"
His father had never been good to him; that - along with his certainty that this was necessary - perhaps made slitting his throat easier. Still the blood - Kin's Blood, King's Blood, Dragon's Blood - is enough to deny him sleep for many a coming day.
Four Dragons breathe upon the Dawn.
iii) Viserys
The bards announce a plot to destroy the Targaryens. The Blackfyres are blamed, as are the Darklyns and a thousand other houses he has barely heard of.
Some blame the Baratheons, a viewpoint he quickly works to stamp out.
None blame him, a reality that he is both grateful for - as it suits his purpose - and resentful off. Rhaegar had always dreamed of being remembered and even the memory of a mad king was better than none. But no, if the truth did come out it would have to wait until the very end when there were no Targaryens left. The prophecy wouldn't allow anything else.
His coronation (and Elia's technically, though his wife has been increasingly sidelined) goes off without any issues. His father was not popular in the court and the Lord of the Realm care little for who sits on the Iron Throne - a small mercy. The maids whisper over how handsome he is - and how little Elia deserves him; a shy, plain, weak-willed Dornish savage.
He does not bother to correct them, there are more important matters at hand.
He cannot kill his brother the same way as his father. Not only does Viserys not deserve it, but the screams - and there would be screams, he's only three -
A Song of Ice and Fire...
The screams would attract help. So it must be poison - quick, painless and certain to kill. And it must get by the food-testers, otherwise his job will be near impossible. He ponders and waits, cunning as the Dragons he is descended from...and strikes when one of the Food Testers fall ill. It is a small thing, nothing major - but enough for a paranoid Targaryen to remove someone from office, temporarily of course.
The following day Viserys falls dead at the dinner table. Rhaella and Elia cry at the loss, Rhaegar just ponders...and waits again.
Three Dragons breathe upon the Dawn.
iv) Rhaella
Rhaegar cries more than he has at any other time when Rhaella's turn comes. She was - is his mother and the prophecy is cruel. Kinslaying is a crime, is it not? Why do the Gods demand this of him?
It does not matter.
Rhaella's guards do not notice him enter her room, they have already been drugged to sleep for hours. They will probably be executed - the court will demand nothing less - but their lives are not important. Their deaths are acceptable in the grand design; the Game of the Gods.
Rhaella barely resists as he smothers her and in some ways that is worse. He feels like a monster to kill this defenceless, pregnant woman - his mother and unborn sibling.
A Song of Ice and Fire...
He presses down harder. The look in her eyes - grief, disbelief, betrayal - he imagines it will follow him forever. He does not go to the Sept to find solace, instead taking a silent walk under the night sky.
He cannot see any stars tonight and even the moon is absent, covered by cloud or shadow he knows not. Just blackness to surround him, blackness absorbing him as an acknowledgment of his sins - blackness aside from one star far to the North.
After all, One Dragon still breaths upon the Dawn.
v) Rhaegar
They find the King's body three hours after he has passed on. Poison they say, self inflicted - out of grief most probably, the poor bastard. With him the Targaryens are finished, the Dragonlords gone forever.
Most assume that the reign of the Stag begins now, a fact made certain by Robert Baratheon's immediate marriage to Lyanna Stark. The wedding is unhappy some say, that this is a marriage that will not bear many babes, that the girl will die in childbirth.
The fact that several of these rumours come from Casterly Rock is unnoticed.
But then Elia Martell reveals her own pregnancy, a desperate hope for those who hope that the dragons will return - and those who hate the Baratheons with a passion. Dorne is quick to support her, as are the Westerlands and the Vale - the latter bringing Robert and his brother over for a time.
A nervous peace, a weak peace but still a peace...
And then the babe is born a girl with no resemblance to her father.
No Dragons breathe upon the Dawn.