Board Thread:Questions and Answers/@comment-5107008-20150316050152/@comment-5398287-20150316113927

At the moment, Uryu is the Crown Prince of the Wandenreich, a faction of Quincies intent on destroying the Gotei 13, appointed by the Father of the Quincy himself - Yhwach. At first, it seemed he had only joined the Wandenreich for a chance to kill Yhwach, who, 9 years ago, had killed his mother, Kanae Katagiri, by stealing her power with Auswählen; said motive was outlined by Yhwach's number two, Jugram Haschwalth, in a brief confrontation he had with Uryu about 50 chapters ago. However, in last week's chapter (619), after the Soul King was killed by Yhwach's actions and Mimihagi managed to stabilize him to prevent the worlds from collapsing, Uryu gave Yhwach the opportunity to continue destroying the worlds by shooting Yoruichi, one of his good friends, in the shoulder; this distracted her from maintaining a barrier she had erected around the Soul King, causing it to shatter. Essentially, Uryu went from "passive bystander waiting for a chance to strike" to "Sasuke", and given the title of the chapter - "The Betrayer" - it is entirely possible that he is now evil.

As for Ichigo, the history of his parents was explored in a mini-arc a couple years ago; Masaki was a pure-blooded Quincy, and Isshin was the captain of the 10th Division. At the time, Aizen was testing out an Arrancar prototype named White in the Human World, so Isshin set out to figure out what was going on and ended up fighting it. Masaki sensed the battle and intervened, leading to White biting her and Masaki shooting it through the head. Isshin managed to save her from the ensuing explosion, and the two met and talked for the first time. However, White had passed on a Hollowfication virus of sorts to Masaki that began, well, Hollowfying her, and in order to save her life, Isshin had to enter a special Gigai created by Urahara that made him human by tying him to Masaki. Then they had Ichigo; Masaki passed on her inner Hollow to her son, and Isshin, still having Shinigami powers that were simply restricted, gave him the potential to wield a Zanpakuto, as well as a signature technique - the Getsuga Tenshō. However, the inner Hollow unexpectedly fused with the Zanpakuto powers, so they became the same source of power for Ichigo. Thus, Ichigo was born as a part-Quincy human with Shinigami and Hollow powers, as well as the potential for Fullbring.

And for Zangetsu, it was revealed that he had only been masquerading as Ichigo's Zanpakuto all this time, and that his real Zanpakuto was, in fact, his inner Hollow, whom Fakegetsu had been repressing all this time; Fakegetsu was really the manifestation of Ichigo's Quincy powers, as well as a portion of Yhwach's power and soul. However, Fakegetsu gave Ichigo access to his real Zanpakuto because he felt Ichigo had grown enough to wield it, so Ichigo now wields the true 'Zangetsu, which incorporates both his Quincy and Hollow powers.

Hope that helps.