Tessarion

Dark blue shot with copper, ridden by the youngest and least monstrous of Alicent's sons.

The beast itself

Tessarion was dark blue, deep as good ink, and the colour ran right through her ÔÇö even her flame came out blue at the heart, which was rare enough that men who had seen it said so for the rest of their lives. Along her wings, her claws and the ridges of her crest the blue gave way to a bright burnished copper, so that in flight she read as a dark shape with a bronze edge to it. She was young, and she was small next to the old monsters of that war, but she was in the fastest, most flexible part of a dragon's life: she could turn inside almost anything, and she climbed like something that enjoyed it.

Her temperament was eager, which is a dangerous quality in a beast that age. Tessarion was quick to rouse, quick to answer, and had none of the sullen weight of the older dragons ÔÇö she wanted to be up, and she wanted to be doing something, and she had no experience whatever of being hurt. Handlers described her as biddable and jumpy in the same breath. Her voice was high and bell-like. Of all the dragons in the Dance she is the one the accounts most often call beautiful without any of the ambivalence they attach to Sunfyre.

Her rider: Daeron Targaryen

Daeron, called the Daring, was the youngest of Alicent's sons and the only one about whom nobody had anything bad to say. He was fostered at Oldtown, well-mannered, well-liked, and genuinely trying to be the thing the songs said a knight was ÔÇö which in that particular war made him something between an ornament and a rebuke.

He and Tessarion were the same age and much the same disposition, and they went to work together in the Reach with an efficiency that surprised everyone. At the Honeywine they arrived over a battle the greens were losing and turned it inside an hour, and the Hightower host that had been about to break instead rolled forward and did not stop. It was a clean victory, well conducted, and it is one of the very few engagements of the Dance that anyone on either side afterwards remembered with any pride.

Then came Tumbleton, and the difficult part of Daeron's story. He took the town properly, by dragon and by force of arms, and his own side ÔÇö dragonseeds and sellswords and men with grudges ÔÇö proceeded to do to it what armies do when nobody stops them. There is no account of Daeron ordering it and every account of him being unable to end it. Watching from the outside, men began to notice that the boy on the blue dragon was the only person in that camp still behaving as though rules applied.

What became of it ÔÇö if an ending is written, it is here. Spoilers.

Tessarion died at the Second Battle of Tumbleton, in a three-way fight among dragons whose riders had largely stopped knowing what they were fighting for.