To say that Yuzu doesn't like Renji Abarai is a gross understatement.
Had her brother died that cold night Renji and his captain left Ichigo bleeding and alone in the open darkness for someone to find (Ichigo's unharmed body next to his mangled spirit) she might have hated him. But, she reasons, pushing back a piece of auburn hair behind her ear, since he did leave with the intent of Ichigo dying, Renji Abarai might as well have murdered her mother's only son—this is why she hates her brother's new friend.
Yuzu isn't known to be hateful or mean; in fact, she has the delusional impression of a sweet little girl imposed upon her by everyone she knows. But, Yuzu finds this forced persona benefits her in the end because she can keep her thoughts and opinions hidden easily. People forget she is around more readily—and she can know things without other people being aware that she knows them.
The only person who Yuzu can count on seeing through her façade is Ichigo. Of course Ichigo has always been able to seethings more clearly than other people. Even Karin and Yuzu for all of their sense and sight cannot touch Ichigo when it comes to seeing things that shouldn't be there.
Still, Yuzu worships the ground that Ichigo walks on because he is her older brother—and because that is what good, sweet little sisters do. She knows that he sees straight through her act, and when he is cold to her or teases her too much she'll even forget herself for a moment and yell at him.
"You're such a jerk!" She'll yell, red in the face, and open her mouth to continue when she sees a smile of victory reach his eyes,
"You're slipping,"His eyes would say, "You don't fool me." And she would snap her mouth shut and run to her room. Karin would yell at him for her later, Karin will be everything Yuzu cannot be. But even Karin doesn't know what Yuzu knows about the day their brother nearly died.
Yuzu followed him that night; she remembers still being awake and deciding to clean the kitchen before trying to fall asleep again. She hated waking up to greasy counter-tops and dried food on plates. Being an eleven-year-old substitute mother left Yuzu with anxiety and anger far beyond her years.
She hears raised voices coming from Ichigo's room and then someone coming down the stairs. Rukia doesn't notice that she runs past Yuzu when she slips out of the front door, and Yuzu had the good sense to dip behind the counter when she hears her brother rush down the stairs several minutes later intent on going after her. It only takes a few moments of hesitation for Yuzu to put on boots and a jacket and then run after her brother.
She felt a rush of spiritual energy release itself and slowly approaches the epicenter of the action. Yuzu ducked behind a tree and watched—horrified when a man with flaming red hair cuts her brother down, and then fiercely proud when Ichigo stands back up to fight him. She is too frightened to yell when she sees all of the blood erupt from Ichigo's chest—but all she wants to do is scream.
"Not him," She thinks hysterically, "I don't know who or what to pray to but please not my brother…I can never have another brother; my family will be broken—not my brother."
Yuzu remembers her anger and indignation watching Renji step on Ichigo's head as he tells him that he doesn't know, "When to give up." And the moment he leans in close to tell Ichigo that he should quit struggling so that he might, "live a little longer," she hates him.
The way that they looked at her brother, her mother's son, Ichigo—they looked at him like he was below them and worthless—the way they mocked him and called him human,it makes her skin crawl. When Yuzu thinks that maybe Rukia will say something—she kicks Ichigo's hand down…but she cannot hate her because Rukia jumped on Renji to save Ichi-nii and tells him to run.
Once the others leave she is on her feet and running towards him, blood covers her hands and clothes and she is crying at him to wake up. Beside her is a boy from Ichigo's school, also bloody but not as bad as her brother. He is telling her to go find help. Before he can finish his sentence Yuzu finds herself running then to Mr. Urahara's shop and pounding on the door, yelling for help. She doesn't understand how but she just knows she will be able to help. She's always had a knack at knowing things. When Mr. Urahara finally opens the door with a sleepy face and disheveled hair, Yuzu is breathing unevenly and half sobbing,
"Ichigo is hurt, someone tried to kill him, I can't—I can't—I can't…" He is quick to respond the moment he sees her covered in blood.
As Kisuke calls for Mr. Tsukabishi he feels a nostalgic chill creep up his spine because he remembers when Yuzu's mother came to him covered in blood, and for the first time he is disturbed by how much she looks like Masaki.
When Mr. Urahara tells her that Ichigo will be safe with him she is relieved, and when Mr. Urahara does something that he thinks will make Yuzu forget everything that happened she plays along…she always does that though.
After, Kisuke reflects on the Kurosaki siblings, as he finds himself doing from time to time, he notes with a lingering sadness how haunted all of their eyes are. He never forgets the night that Yuzu came to him, brown eyes full of fear and grief and panic;"She should be in bed dreaming peacefully…" But there she was, protecting her family in the ways her mother no longer could (If today I don't do what I can because of some custom and someone dies because of it, I won't be able to forgive myself tomorrow).
Yuzu gets angry as she watches her brother make a larger assortment of new friends and she has to endure Renji's presence while she walks home from school with her brother and sister.
There is a bald one, a feminine man, and a small white haired boy (along with Renji) most frequently. She wants to ask them who the hell they think they're fooling because they look too old (or young) to be in high school. To quell some of her pent up rage she starts spreading nasty rumors in the high school about all of them via her friend's older sisters.
"I heard that Abarai kid did time in a prison."
"I heard the three tall ones have been held back twice already."
"The little one with the white hair runs drugs around for a gang. I've seen him running around constantly whenever his cell phone goes off—who knows where he's going…"
She bites back her smile whenever they complain about how gossipy humans are or how pathetic it is that these kids have nothing better to fill their time with…but she knows that it bothers there is one thing any observant girl can confirm, it's that men have tiny and fragile egos.
Whenever they come into her house she is sure to make herself scarce, she doesn't want to make them food or bring them drinks. Sure it's common courtesy to cater towards the needs of guests…but one of these guests tried to murder Yuzu's brother and it makes her sick that he's even in her house.
She knows Ichigo does dangerous things for them—these adults that aren't even from their world use her older brother, who is still just a kid, to complete their dirty work. But she probably wouldn't have even minded that if it hadn't been for him. At first Renji wanted to humiliate and kill Ichigo and now he can't wait for her brother to come to his aide? Yuzu's fists clench even thinking about it. She is nearly ashamed by her anger and always surprised by her hatred.
The way he is so disrespectful and belligerent grated on her nerves. She finds herself dreading having to go to Urahara's Shop when Karin wants candy because Renji will be their pretending to sweep the floors or arguing with Jinta (the boy who gave her free stuff and was really nice to her but not to that other girl) or just existing with that smug look on his face.
She has to be the world's greatest actress then because if she loses concentration for a moment she will be scowling—and Yuzu Kurosaki doesn't ever scowl. At her age Yuzu finds that tears are her best weapon (she doesn't know of the other one yet)and that scowling only makes her face look ugly.
Her father tells her silly things to make her smile, her sister chastises Yuzu for crying so much but understands why she does it, and she knows Ichigo would defend her no matter what; so, Yuzu has to protect them. Her mother is dead now and it is up to her to keep them safe…because they are all very head strong (especially her siblings) and they are not always right (especially her Daddy). She is bewildered with love.
And so when Yuzu sees that her brother has decided to become friends with his would-be murderer she is appalled. She cannot wait to be older, she reasons, because then a death threat would be taken more seriously,
"If you ever hurt my brother again," Yuzu would say with a deadly voice and an icy glare, "I will do whatever is in my power to hurt you."