5. Aegon I, Visenya, and Rhaenys Targaryen
Let’s start with the trio that created the dynasty. The conqueror Aegon and his two sister-wives were a stunningly effective political unit. While their union set a controversial precedent for incest that other houses viewed with suspicion, their internal
dynamic was mostly functional. Visenya was the stern warrior, Rhaenys the charming diplomat, and Aegon the decisive leader. They complemented each other. Any squabbles (and lore suggests there were plenty, especially between the sisters) were kept private. Their sibling bond didn't fracture the realm; it forged the Iron Throne and established nearly 300 years of Targaryen rule. In terms of political damage, they’re in the green. They are the benchmark against which all future failures are measured.
4. Maester Aemon and King Aegon V
This one is subtle. The dynamic between Aemon and his younger brother Aegon “Egg” V caused damage through its absence. When Egg unexpectedly became king, his older brother Aemon voluntarily went to the Night’s Watch to become a maester. He did this to remove himself from the line of succession, wisely preventing any chance of a rival claim destabilizing his brother’s reign. An honorable move, right? Yes, but the long-term cost was immense. By taking himself out of the game, Aemon deprived the capital of one of its sharpest minds. Decades later, when the dynasty began to truly unravel under the Mad King Aerys II, the wise counsel of a man like Aemon was desperately needed in King’s Landing, not wasting away at the Wall. His absence was a quiet but significant political loss.
3. Viserys and Daenerys Targaryen
Here the damage becomes direct, personal, and pathetic. As exiled orphans, Viserys was all Daenerys had, and he used that position to abuse her, belittle her, and treat her as a mere commodity to be sold for an army. His obsession with reclaiming the Iron Throne wasn’t just arrogant; it was strategically inept. By marrying Dany off to the Dothraki, he set in motion a chain of events he couldn't control. The long-term political damage wasn't his sad, golden-crowned death. It was the creation of Daenerys, the Breaker of Chains—a ruler forged in trauma and fire, with no connection to Westeros and a dangerously messianic complex. Viserys’s cruelty incubated a force that would eventually land in Westeros like a comet, ultimately leading to the destruction of the capital.
2. Daemon and Viserys I Targaryen
If Aegon and Rhaenyra were the civil war, Daemon and Viserys were the decades-long cold war that preceded it. The relationship between the steady, peace-seeking King Viserys and his brilliant but chaotic brother Daemon was the central fault line of the era. Viserys’s love for his brother blinded him, causing him to forgive transgressions that should have led to exile or execution. Daemon’s ambition and resentment, coupled with his genuine affection for his family, made him a deeply unpredictable force. He antagonized the Hightowers, flouted tradition, and created instability just by existing. Every action Viserys took to control Daemon, and every reaction from Daemon, deepened the cracks in the court, empowering factions and forcing lords to choose sides long before any war was declared. Their toxic codependency practically handed a lit torch to their children.
1. Aegon II and Rhaenyra Targaryen
This is the big one. The main event. The sibling rivalry that broke the Targaryen dynasty. While Rhaenyra and Aegon II were personally more like pawns in a larger game orchestrated by their parents and grandparents (looking at you, Otto Hightower and Viserys I), their names became the banners for a war that tore the Seven Kingdoms apart. The Dance of the Dragons was a complete political apocalypse. It resulted in the deaths of thousands, the near-extinction of the dragons, and the decimation of the Targaryen family tree. The house never truly recovered its strength or mystique. The dragons, the ultimate symbol of their power, were reduced to withered skulls. All subsequent Targaryen weaknesses, from the Blackfyre Rebellions to their eventual overthrow, can be traced back to the catastrophic precedent set when Targaryen fought Targaryen, sister against brother. No other sibling dynamic comes close to this level of realm-shattering, dynasty-ending damage.
