Yūichi Shibata

was a Human boy whose mother was killed by the Hollow Shrieker when the latter was a living serial killer.

History
According to Shrieker, while he was killing Yūichi's mother on a balcony, Yūichi grabbed his shoelaces and sent him tumbling down. After Shrieker became a Hollow, he sucked out Yūichi's soul and put it in a cockatiel.

Agent of the Shinigami arc
One night, one of Chad's friends, Harutoki, brings the cockatiel to where he, Shigeo, and Chad were meeting. He explains that all of the bird's previous owners died horrible deaths, and so the bird passed hands quite a bit. Harutoki offers the cockatiel to Chad, and almost immediately, a girder drops down on them. Chad quickly catches the beam, although he is severely injured in the process. Then Yūichi thanks Chad for saving him, asking what his name was. Chad and his friends are surprised that it could talk, although Chad responds to it.

The next day, after halting Ooshima from using iron knuckles to attack Ichigo, Chad shows Yūichi to Ichigo, Keigo, Rukia, and Mizuiro. Yūichi quickly reveals his ability to talk comprehensively to them, and Keigo eagerly begins a conversation with him, while Rukia and Ichigo attempt and fail to press Chad for details of what happened the night before. Rukia figures out that Yūichi is a lonely spirit, but could become a Hollow, so she decides that they must perform Konsō on him that night.

Later that day, the Kurosaki Clinic is extremely busy due to a car accident. Ichigo is asked to carry Chad indoors. While he is doing so, Karin notices Yūichi, who is still with him. Chad quickly leaves that night, with Yūichi.

Chad and Yūichi are seen hiding in a warehouse the next day. Yūichi asks if Chad is alright, to which Chad replies that he's tough, so he'll be alright. Suddenly, the roof comes down on them. Chad dodges the falling debris, but Yūichi says that they were found by "it". Chad gets ready to run away, promising Yūichi that he will save his mother. However, they immediately run into Ichigo and Rukia, who were looking for them. Chad quickly turns and runs in another direction, while Ichigo is forced to pull back because Karin was suffering from memories that Yūichi unintentionally transfered to her about his mother's death.

However, Chad stops when he hears the sounds of fighting. Yūichi says that Rukia, who continued chasing after them, is now being attacked by the one who brought the roof down on them earlier. Chad quickly puts Yūichi's cage down, saying he'll go help Rukia. Yūichi shouts for him not to, because it's dangerous. Misunderstanding what he meant, Chad puts the cage up on a wall. Yūichi clarifies what he means: Chad can't see ghosts, so Chad has little chance of standing up to their pursuer. But Chad is already dashing off at that point.

However, Yūichi's cage is soon attained by his pursuer: a Hollow named Shrieker. Chad is surprised as to why Yūichi is there. Rukia tells him not to make a move to rescue the cockatiel, because Shrieker can destroy him with his exploding leeches. However, due to Ichigo's intervention, Chad is able rescue Yūichi. As Rukia tells Chad to take Ichigo's body and Yūichi out of the area, Yūichi begins to blame himself for their injuries, and he made them go through everything because he wanted his mother to come back to life. Rukia immediately presses him, asking if someone told him that there was a way to do so.

That night, after Shrieker was killed, Rukia and Ichigo prepare to perform Konsō on Yūichi. Rukia informs the boy that he can no longer return to his original body, so they can only send him to Soul Society. Ichigo adds that if he goes there, he can see his mother again. Yūichi eagerly agrees to being sent to Soul Society, but then looks back at Chad. As Yūichi's spirit form begins to materialize, he thanks Chad for all the time they spent together, because Chad made sure he never got hurt once. Chad asks if when he goes to Soul Society as well, if he can carry Yūichi around once again. Yūichi happily agrees, and Ichigo sends hims off.

Soul Society arc
Shibata appears again in volume 9 and fulfilled an earlier promise with Chad that he would let himself be carried. He joined a surrogate family with Horiuchi Hironari acting as his older brother. He had not yet found his real mother, which is partially due to the fact that souls are sent to separate districts in Rukongai, even if they are family, making it extremely difficult to locate a single person.

Appearance in Other Media
In the video Game Bleach: Dark Souls, Yūichi is an unlockable character. He is very weak because of his size and poor range, easily making him the weakest in the game.