Originally, the family was pure blood, Echt Quincies, ones who only married other purebloods to sustain their line. Ryuken was to marry Masaki Kurosaki to sustain the line, but due to a hollow incident & the kindness of Isshin Shiba, she chose the soul reaper over Ryuken. Masaki didn't speak ill of Ryuken for coming to do what he felt was right either, but because she chose Isshin, Ryuken would have to break their pureblood line...something he didn't feel was right, but he didn't want Masaki to suffer either. Kanae, the maid of the Ishida mansion stepped up in Masaki's place as she couldn't stand to see Ryuken suffer either. Kanae loved Ryuken & despite the ugliness the rest of the house thought of Kanae being with Ryuken, Soken understood that their family would have to make the sacrifice of their pride as pure bloods since there were already so few Quincy left.
Kanae gave the Ishidas the first Gemischt of their line, Uryu. Dark hair like Kanae & bright blue eyes like his father, but his power was unlike anything the family had ever seen. He was a smart cookie, genius intellect from a young age & sharp with words, but he had a strong heart. He once feared his powers & hated that he wasn't strong enough to protect Soken when he was killed. Out of that hatred came a will to fight to become the strongest in their family & he gave his father a week long fight to earn his powers back after he sacrificed what little he had gained to keep Orihime safe.
Ryuken loves his son, even though he's cold about it most of the time. He's overheard his nurses speak of how beautiful Uryu is now...they said the same thing when he was born & now the youngest of them look at him with starved eyes. Ryuken is not letting them go after his son...at all! Ryuken had already been through a failed attempt at an arranged marriage & Kanae was his pick...which ticked everyone off. Uryu wasn't about to be bothered by his workers & it takes all Ryuken has to keep them away from his son.
Not like Ryuken minds too much though, he's proud of his son for being so pretty that he's bragged about. "If he knew how much they talk about him, he'd really have a fit." The nurses have seen Uryu without his glasses & when he doesn't wear them...he gives off the bad boy vibe of his father while holding the innocence of his mother. Ryuken takes it in his stride though, knowing his son is well liked at his job & is spoke high of makes him happy. Uryu gets the best grades at school too & is rarely in trouble because he's always helping out somewhere. As long as Uryu can fight when he has to & live comfortably, Ryuken doesn't make a fuss about his son being rebellious & going with Ichigo for the most part.
Uryu is the last of the Ishida line & the last firstborn Gemischt Quincy of the once pure line. He is the last mixed-blood alive & the first mixed-blood to the Ishida family, but also the only Gemischt to have an immunity against Yhwach. He alone has the power to stand against the Quincy King...for he not only has the power to defend against the Auswahlen, he can use powers that a lot of the Quincies didn't have that are rare. Mayuri spoke of the Ransotengai being a power Uryu has that most of the Quincies that he'd researched didn't have & if they did, they were elders...until him. Uryu is the youngest of the archers to know & use something that usually the elders were well trained in due to age. Soken trained Uryu well & Ryuken isn't letting his son not have his powers to fight. Kanae was already taken from him & Soken was killed...he'd be damned if he lost his only son! Uryu is the rarest Quincy of all & Ryuken won't let Yhwach take away his only kid. Out of the still silver in Kanae's heart, Ryuken forged an arrowhead to use against Yhwach, but knowing he'd more than likely be killed if he raised his own bow against the Quincy King, he gives to Uryu. Ryuken has known all along that Uryu was special & him surviving Yhwach's Auswahlen moved him into wanting to defend Uryu at all costs. Ryuken didn't want him to go after his Quincy powers at first, but he's kept up on his son's growing powers. "I can't avenge Kanae, not without risking my life in getting killed like she got done. Uryu can though & he deserves to avenge her. We were both broken from losing her & to take the life of one who did no wrong is wrong in itself."
Uryu is the avenger of Kanae & all the Gemischt that died with her. The revenge of the mixed-bloods is Uryu Ishida, their powers are what make his Antithesis so strong. Their hatred at being ended for being impure flows through his bow & their desire to rest in peace flies in every arrow he fires. He may be the last of the Gemischt, but he is the most powerful of their type & none of Yhwach's followers expected him to be the sole survivor. "Yhwach stole my mother from me & my father, yet she did nothing to deserve her death by his hand. I didn't expect my father to make an arrowhead from the still silver in her heart, but I wanted to avenge her at least. We both agreed on that & there's nothing more we wanted than to avenge her at least. I guess...after all these years...I can finally admit that dad did want the best for me, but I was too hurt from losing mom to see it."