Bleach's Ichigo Kurosaki is the hero, but he's a hero for more than just his combat strength. He certainly has a sharp Zanpakuto and a powerful inner Hollow, but it's his good heart that makes him a true protagonist and hero to his friends. The same could be said of Uryu Ishida, his Quincy ally.
On paper, Uryu should be Ichigo's bitter rival and enemy. He is a Quincy, a natural rival of the Soul Reapers, and indeed, his beloved grandfather Soken Ishida was kidnapped and killed by Captain Mayuri Kurotsuchi, the scientist Soul Reaper. Uryu is smart, yes, but it's his good heart that's his best weapon in the battle against evil.
Uryu Ishida was born a Quincy, inheriting those powers from his grandfather Soken and his father, Ryuken. Quincy are supposed to be bitter towards the Soul Reapers, but Uryu was more concerned about spending time with his loving grandfather. Uryu had a positive mentality and a great deal of optimism, setting him apart (for the time being) from his pragmatic, money-minded father Ryuken. As a boy, Uryu had the time of his life training with his grandfather, and was heartbroken when Soken was captured and dragged off to Soul Society so Captain Kurotsuchi could experiment on him. Uryu's could have been hardened by hate, but that's not really what happened. He enrolled in high school and soon learned to make friends his own age, even if it took him time to swallow his Quincy pride a bit.
Uryu was smitten by his classmate Orihime Inoue, who was also Ichigo's friend. More than anything, Uryu wanted to keep Orihime safe and see her smile, acting on these warm feelings during the Soul Society arc, and again during the Hueco Mundo arc. Most significantly, Uryu slowly but surely extended the hand of friendship to Ichigo, his Soul Reaper classmate, even though Uryu's rational mind told him to see Ichigo only as an enemy. Uryu is well-read on Soul Reaper and Quincy history, and he's calculating and methodical in everything he does. Despite that, Uryu's strength of heart led him to form a fruitful alliance with Ichigo Kurosaki. Alone, neither Ichigo nor Uryu could have accomplished the things that they did in Soul Society or the desert realm of Hueco Mundo.
If Uryu listened to his rational feelings instead, he would have been in no position to rescue Orihime from Las Noches, likely only caring for himself. He would have fixated on his thirst for revenge on the Soul Society, plotting their downfall and siding with the Wandenreich even sooner than he did. Uryu may have been downright miserable if he relied on his intelligence alone. Being a cold, lonely genius would have weighed heavily on his mind and wounded his heart, and Ichigo, Chad and Orihime would have missed out on a vital ally.
Many important scenes in Uryu's quest prove that while he makes good use of his advanced intelligence and cunning, it's his heart that really allows him to realize his potential. It was out of love for his grandfather and a lot of his heritage that Uryu trained so hard to become a proper Quincy archer, and at age 15, when he confronted Ichigo, he was already in a position to make some new friends, even if he didn't think so at the time.
Uryu broke the ice with a Hollow-slaying competition with Ichigo, but the two boys soon joined forces to storm the Soul Society, along with Orihime and Chad, to rescue their friend Rukia Kuchiki from her fate. Uryu was driven to protect the innocent Rukia's life, and that gave him some excellent live-fire training against hostile Soul Reapers. He was also burning to protect Orihime, and that drove him to extraordinary heights when fighting Captain Kurotsuchi.
Uryu trained with his father to regain his powers, but he largely ignored Ryuken's cold demand that he cut all ties with Ichigo and the Soul Reapers. Uryu was in no mood to accept Ryuken's icy logic and remain pure to the Quincy way; he had friends, and it didn't matter if those friends were Quincy, Soul Reaper, human or anything else. This led Uryu to volunteer to help Ichigo rescue Orihime in Hueco Mundo, and Uryu was riled up when he saw the vicious Ulquiorra Schiffer kill Ichigo in cold blood and threaten Orihime's life. Uryu had friends to save, and the logical consequences be darned; he would face Ulquiorra with all his might, and even though he was struck down, it was truly heroic and inspirational to see Uryu like that.
Finally, Uryu was offered a place in the Quincy Wandenreich, and logic demanded that Uryu pledge total fealty to Yhwach, his Quincy king. But Uryu didn't listen to those thoughts; he had an unbreakable bond with his friends, and he believed in what they stood for. In the end, Uryu turned on Yhwach and helped bring about his downfall, shooting an arrow into him that allowed Ichigo to strike the final blow.
