Honkai Impact 3rd vs RWBY
Connection:
Both are determined and fiery redheaded female heroines that are beloved by fans of their respective series
Both attend a school led by a white-haired principal (Theresa Apocalypse and Ozpin) that trained superhuman defenders (Valkyries and Huntsmen/Huntresses respectively) to fight against the threat on their worlds (Honkai and Grimm respectively). The contrast is that Himeko is a teacher whereas Pyrrha is a student
Both were given a choice that could change their lives for the better or worse (Himeko is given a serum which would cure her of her Honkai infection that would allow her to live longer, but would be unable to fight as a result. Meanwhile, Pyrrha is offered by Ozpin to become the next Fall Maiden to prevent Amber's assailant from claiming the other half of her powers, but is unsure if she is ready). But it was taken away from their albeit in different ways and circumstances (Himeko used the serum on HotV to free Kiana whereas Cinder killed Amber to fully claim the Maiden powers)
Both were killed by a major villain in their last stand (Sirin/Herrscher fo the Void and Cinder Fall respectively), but their deaths pushed to the ones affected by their passing (Kiana Kaslana and Ruby Rose respectively) to move forward and gain new abilities (Kiana is able to use HotV's powers with Void Drifter while Ruby unlocked her Silver Eyes which are deadly against Maidens and Grimm, which Cinder has both)
Not much, but both also have songs that causes fans to tear up when first played (Nightglow and Forever Fall respectively)