Why did Vermithor accept Hugh Hammer?
Hugh does not wait passively for Vermithor to choose him. He challenges him.
The Red Sowing is the closest House of the Dragon comes to staging a massacre as a recruitment process. Mysaria (Sonoya Mizuno) helps put the dragonseed idea in Rhaenyra's head, and a crowd of Targaryen bastards is eventually brought before Vermithor. Most do not survive. Hugh does.
Then, when Vermithor turns on a fleeing woman, Hugh puts himself between them. He stands his ground, and Vermithor accepts him.
That distinction matters. Hugh is not accidentally discovered by the right dragon. He sees an opening and steps directly into it. The bravest thing Hugh Hammer ever does is also the most ambitious.
There is also a family symmetry underneath the scene. The show all but identifies Hugh's mother as Princess Saera Targaryen. Hugh describes a silver-haired mother with Targaryen blood who worked in a pleasure house and spoke of her royal relatives in ways that point heavily toward Saera.
If that identification is correct, King Jaehaerys I was Hugh's grandfather, and Vermithor was Jaehaerys's dragon.
That does not mean Hugh inherits Vermithor. Dragons are not estates that move neatly down a family tree. But the image is difficult to miss. A man who has spent his life hidden from his royal ancestry ends up riding the dragon of the king at the top of it.
Hugh had kept that part of himself buried for years. Even Kat does not learn the truth about his mother until he is preparing to leave for Dragonstone.
And when he finally gets Vermithor, he does not immediately start talking about crowns. What Hugh wants is still recognizable: status, security, a life in which powerful people cannot simply ignore whether his family survives.
Rhaenyra does elevate him. She does not simply hand Hugh a dragon and give him nothing in return. He is brought into her war, given status and treated as somebody whose household should now have a future. The tragedy is that those rewards arrive too late to do the job Hugh wanted them to do.
Power finally notices Hugh after power has already taken almost everything from him.