Alright, this'll be a bit of rant.
See, you might notice I mention Rukia's "Family" in a rather negative tone, because I seriously dislike them all, and only one of them is blood related anyway.
The 'Soul Society' is pretty much a 3rd world slum, not the paradise afterlife you might imagine, and Rukia was seemingly born a soul, still a newborn baby before she was abandoned by her guardian, her adult sister, and left to die, while she ran off to live in luxury with the a royal noble, Byakuya.
Somehow Rukia survived and as a child ended up joining a band of other vagabond orphans to survive, one of them a guy called Renji.
Eventually all their friends died and the two survivors decided to become Shinigami.
Soon after joining the academy, Byakuya noticed Rukia's resemblance to his now late wife, and forcefully adopted her as his sister.
He was a piece of shit to her, but that's another story.
Renji went full coward mode at this point, and was too afraid to ever speak to Rukia, instead rising through the ranks, eventually coming becoming the Lieutenant to Byakuya.
Rukia went through some awful shit unrelated to all this, and volunteered to perform missions in the living world, to clear her head.
Then an incident with the MC happened, almost killing them both, resulting in Rukia transferring her powers to the MC.
This is felon for Shinigami, and Rukia was to be arrested, Byakuya and Renji were sent to retrieve her.
After not seeing her for 40 years, Renji ambushes a powerless Rukia, slashes at her repeatedly with his sword, before slamming and choking her against a lamp post.
Rukia is soon after taken away, jailed and put on death row, she was to be executed.
Renji visted Rukia at this time and he gloated at her and claimed she deserved to die.
While it's true he was apparently conflicted, he was being a complete cunt.