The Real Villain of House of the Dragon Is Not Who You Think
Although perhaps indirectly, this character from the GoT prequel series can be considered the main villain of the show's first season.
House of the Dragon, like its predecessor, is full of intrigue, elaborate plots, and battles for the Iron Throne.
The main conflict of the prequel series, at least its first season, revolves around Rhaenyra Targaryen, daughter of King Viserys I, and Alicent Hightower, a childhood friend of Rhaenyra's who became queen after marrying the king.
And while fans continue to argue which of the two is right in their claims to the throne since, in a classic Game of Thrones fashion, it is a gray area and things are not that simple, they seem to be ignoring the one who is fully responsible for the situation in the first place.
The aforementioned King Viserys I, portrayed by Paddy Considine, could be considered the main villain of the first season of the series, as if not for his decisions, the conflict could have been avoided.
First of all, he knows that his Hand, Otto Hightower, is against Rhaenyra becoming queen, and yet he marries Otto's daughter Alicent, knowing full well how many problems that will cause.
He completely neglects his children with Alicent, though he has every reason to love them.
Aegon is the son he wanted for years, Aemond is a smart young man interested in history like his father, and Helaena is the dreamer Viserys himself wanted to be.
When Aemond loses an eye, Viserys completely gaslights Alicent and her children with no punishment whatsoever for Rhaenyra's child.
While an eye for an eye is too harsh, there should have been some repercussions. Instead, this event only escalated the conflict between the women.
As for Rhaenyra, first he allows her to attend meetings and other events, clearly preparing her to rule by having her learn politics, then he doesn't defend her against Otto and even puts her in charge of choosing a knight, which is like telling her to go away.
And finally, when Viserys began to resemble a walking corpse in his final years due to his advancing illness, he should have crowned his daughter and ended the fight for the throne before it even began.
So as you can see, even if some of the things mentioned above were not done on purpose, King Viserys I can be considered the indirect main villain of season one due to his routinely bad decisions.
Source: Reddit