Maybe that is future Ruby
There are theories going around that Ruby has to give up old parts of herself that are linked to her family so she can truly become her own person she first lost yang she lost crescent rose
witch she based off of crows weapon who was her teacher she lost summer before she even got to know her and then she had to give up the emblem she in summer shares so what if this person we're seeing in the weapon isn't summer but a future
Ruby look at how the emblems on her cape look different because that's not summer it's future Ruby look at her closely Ruby's going back to a similar hairstyle she once had before she's wearing a red choker and she's highlighted her outfit with
instead of silver she's added gold to her outfit now possibly even to represent a partner she might have in the future, Ruby will move on from being in her
mother's Shadow and be her own person the same how many other characters have shown they've changed and moved out of other character shadows and become their own person like ,emerld,John ,Oscar Nora, blake ,penny,Weiss and now it's Ruby's turn
This truly could be future Ruby she even has a choker like Ruby does unless this is a hint at what future summer will look like when he we see her again in the series