A Knight of the Seven Kingdoms was a mirth-filled romp compared to most of what we've seen from the Game of Thrones universe on HBO. But with the trailer for the third season of House of the Dragon, it looks like we're back to the backstabbing, relative-humping grimdark fantasy that so many folks know and love. As usual, there's a whole lotta people spilling a whole lot of blood over control of the Seven Kingdoms. There's screaming! Swords! Dragons! A chair made of swords! People screaming as a dragon watches them sit on a chair made of swords! And you can see it all starting June 21. Previously: A Knight of the Seven Kingdoms looks great House of the Dragon hopes to make Game of Thrones great again A Knight of the Seven Kingdoms looks great I tried hard to get into House of the Dragon. I watched every episode, but it bored the hell out of me. There was gore and political intrigue, sure.…