Played to perfection by Paddy Considine, there is an inevitability about Viserys' demise, foreshadowed through both words and physical tells. Viserys is proof that life as a monarch is no cakewalk, despite everybody else's yearning for the Iron Throne. Many harsh realities come with being Viserys Targaryen.
Spoilers ahead for House of the Dragon.
Throughout the first few episodes of House of the Dragon, numerous characters have discussed how placing a woman as the ruler will not stand. The threat of war has lingered throughout as being synonymous with a queen succeeding a Targaryen king. Viserys insisting on Rhaenyra being his heir is either a persisting devotion to his late wife Aemma Arryn or sheer ignorance of what will happen.
Viserys is loyal to the traditions of passing the Targaryen visions down through successors but is so focused on the far future that he can't fathom anything like the Dance of the Dragons happening. The harsh truth of the situation is that Viserys is unwittingly the cause of a major blip in his family's legacy and history.