3. Willas Tyrell
Although he doesn't appear in person in the books, Willas is one of those characters who still plays an important role. The eldest son of Mace Tyrell, Willas was injured in his first tourney fighting Oberyn Martell when his leg caught in his horse's stirrup while he was falling, causing the horse to fall over and crush his legs. Although Willas felt no ill-will towards Oberyn, the incident led to the strong animosity between the two families. Because he could no longer be a knight, Willas rededicated himself to scholarly studies and is considered to be very intelligent. Willas is the focus of several arranged marriages during A Storm of Swords. Originally, Olenna Tyrell (mother of Mace Tyrell) offered to marry Sansa to Willas, something that Sansa wants to accept. However, after Sansa tells Dontos, the knight-turned-fool who wants to help her escape King's Landing, the plan, he tells Petyr Baelish, who tells Tywin Lannister. This prompts Tywin to hastily marry Sansa to everyone's favorite dwarf Tyrion. Later, Tywin offers the Tyrells a marriage between Cersei and Willas, both as a way of uniting the two families and to quiet rumors of Cersei's incest with Jamie. Unfortunately for Tywin, Mace Tyrell refuses this offer. You may be asking yourself, "Why did he include a character that doesn't appear in person in the books." The reason I mention Willas is that in the TV series, Mace's only children are Loras and Margarey. For the first three seasons this didn't present any problems and the writers just substituted Loras for Willas when necessary, such as arranging a marriage between Cersei and Loras rather than Willas. Here's the problem: the Martells are going to be introduced in season 4, and the feud between them and the Tyrells are crucial to the story. Without Willas' injury, there is no reason for the two families to hate each other, which is going to cause complications for the show's story progression. The writers painted themselves into a corner by stating that Loras is Mace's only son, so it's doubtful that we'll ever see Willas on the screen. We'll soon find out what led to the conflict between the two families in the TV show, but it would have been so much easier if the writers had just made one mention of Willas being one of Mace's younger sons.