Beginning in House of the Dragon episode 5, Criston Cole became one of the series' most hated characters. After sleeping with Rhaenyra, Criston attempted to relieve his guilt and shame by asking her to flee with him to Essos. When she rejected his offer due to her duty to the realm (and because she didn’t love him), Criston’s fury turned into bitterness and greater shame, which culminated in the knight gruesomely murdering Ser Joffrey Lonmouth at Rhaenyra and Laenor’s wedding. Fast-forward ten years, Criston was still bitter over Rhaenyra’s rejection, childishly insulted her, hypocritically shamed her for taking Ser Harwin Strong as her lover, and treated her young sons with undeserved cruelty.

Criston continued to show his true colors as he and Alicent bonded over their shared bitterness toward Rhaenyra, which led to Criston championing Aegon’s claim to the Iron Throne. Part of the reason why Criston is so disliked is that his ambition and motivations for power aren’t for himself, but to spite Rhaenyra. Otto Hightower may be a major villain in House of the Dragon, but his desire to keep Aegon on the Iron Throne is entirely self-serving, having little to do with Rhaenyra herself. Out of the main figures in the usurping Green party, Criston has the least compelling reason for betraying both Rhaenyra and King Viserys.