Summary House of the Dragon season 2 has changed one new character's story from the book, but it's still laid the foundation for a related future betrayal. As war breaks out in Westeros, House of the Dragon's cast has expanded in season 2 as the Blacks and the Greens look to add new houses to their cause for the Dance of the Dragons.
Gwayne Hightower’s Role Is Different In Fire & Blood Gwayne Hightower Is In The Greens' Army In HOTD, While He's In The City Watch In Fire & Blood Ser Gwayne Hightower is another character who's been changed for the TV series. In the book, Gwayne is one of the commanding officers in the City Watch, the garrisoned military force of King's Landing that doubles as the city's police.
Eventually, Rhaenyra Targaryen will seize King's Landing from the Greens, storming the city and taking the Iron Throne when Criston Cole and Aemond are too far to send aid. One of the pivotal moments of this event is when Luthor Largent takes Gwayne captive, killing him, as he commands the City Watch to turn on Aegon II and the Hightowers.