"House Of the Dragon."

HBO's prequel to "Game of Thrones" started off slow, with issues, but managed to reinvigorate itself this week and create its own identity.

I doubt anyone at HBO or those creators who vied to helm one of the 87 potential spin-offs to “Game of Thrones” was overly worried about living up to the original. Few shows ever do — “Better Call Saul” is one of the rarest ones but you can fritter your time away constructing others, halfheartedly — and no matter what “House Of the Dragon” did in the ea…