Total number of claimants:
A score of the queen's own household knights offered themselves as dragonriders, amongst them the Lord Commander of her Kingsguard, Ser Steffon Darklyn, along with squires, scullions, sailors, men-at-arms, mummers, and two maids.
20 household knights, incl. Steffon Darklyn, 2 maids, others not specifically counted.
Sixteen men lost their lives during an attempt to become dragonriders. Three times that number were burned or maimed.
Totals 16 and 48 respectively.
Steffon Darklyn was burned to death whilst attempting to mount the dragon Seasmoke. Lord Gormon Massey suffered the same fate when approaching Vermithor.
That´s 2 named dead.
A man called Silver Denys, whose hair and eyes lent credence to his claim to be a bastard son of King Maegor the Cruel, had an arm torn off by Sheepstealer. As his sons struggled to staunch the wound, the Cannibal descended on them, drove off Sheepstealer, and devoured father and sons alike.
Plural. At least 2 sons. So a minimum of 3 dead.
The largest and oldest of the wild dragons was the Cannibal, so named because he had been known to feed on the carcasses of dead dragons, and descend upon the hatcheries of Dragonstone to gorge himself on newborn hatchlings and eggs. Would-be dragontamers had made attempts to ride him a dozen times; his lair was littered with their bones.
When had dragon taming been allowed or encouraged before? How many Targaryen princes or princesses had died trying to tame Cannibal? And at which age?
Also, Vhagar is described as big enough to ride a horse down his gullet. How good is a big old dragon like Cannibal at getting meat off the small human bones? Could a dragon chew up the bones with the meat on them instead?
None of the dragonseeds were fool enough to disturb the Cannibal (any who were did not return to tell their tales).
Yet the total dead is specifically given as 16. And the previous 12 attempts did get recorded (though possibly some of the 12 had survived).
Sheepstealer proved easier to flush out, but he remained a vicious, ill-tempered beast, who killed more seeds than the three "castle dragons" together.
2 named victims of Vermithor and Seasmoke. The minimum 3 of Denys & Sons attributable to Cannibal means meximum of 13 for all others, no one found Grey Ghost, so a maximum of 6 for castle dragons.
Alyn Velaryon would carry the scars of the encounter on his back and legs for the rest of his long life. Yet he counted himself fortunate, for he lived. Many of the other seeds and seekers who aspired to ride upon Sheepstealer's back ended in Sheepstealer's belly instead.
Maximum of 11, because 2 named victims of castle dragons, and minimum 3 of Cannibal.