Early in the RWBY loops, Blake had a fused loop with the Naruto universe as an Uchiha and has since ever considered Sasuke her brother. At one point, she begins to think how delusional such a claim is since countless other loopers have looped in as blood relatives to Sasuke before. Sasuke himself sits her down in one loop and very plainly snaps her out of her Heroic BSoD by pointing out the feeling is completely mutual in that he always sees Blake as his little sister, regardless of their loop scenarios.
In a early loop where Ruby was teamed up with a non-looping Cinder, Mercury and Emerald, the version of Cinder comforted Ruby as Yang in the Loop was in Neo's canon role, while still being her sister, and Weiss was in Cinder's canon role. In this loop Cinder was orphaned when Mountain Glen fell, having been thrown out of the place before the doors slammed shut, and her parents died. She wanted to destroy everything when she was old enough....but realized she'd be inflicting the same pain she felt on others.
The arc of Cinder Falls character. Cinder originated from a Loop that had her wanting to destroy Vale for not understanding the cost of survival. When she started Looping, she remained hidden for a period of time before pretending to have come from a Variant Loop where she was the sister of Ruby Rose. After this she spent several epochs building a grant scheme to fulfill her end desire: destroy Remnant and become a Goddess in the process. However, the unconditional love and respect and trust Ruby placed on her gradually wore her down until she finally snapped from the stress of living two lives, resulting in one Good and one Evil Cinder. Cinders plan to become a Goddess came to a head in what Ozpin deemed the Tale of Two Sisters where Cinder kidnapped Ruby and used her power and the absence of the strongest entity in Remnant in an attempt to fully Ascend. Her plan failed though, due to her mounting psychosis,essentially defined as her benevolent personality resisting her malevolent side. This culminated in a revived Ruby confronting Cinder and reminding her of all the good times and all of the love they shared as sisters, an act that managed to break through to Cinders heart and brought her back from the edge. As the Loops have since progressed, Cinder Fall has walked a fine line between cold villain and doting sister, but the former has never overridden the latter. Cinder has truly become a Cool Big Sis to Ruby Rose, and she wouldnt have it any other way.
In general, a Loop where the characters have a chance to set things right. Remnant is a screwed up place filled with screwed up people, but when the Loopers get a solid chance to improve the world they buckle down and fix Remnant.