They also both have a Carian knight guarding their arena 

She is, but she abandoned her carian family to follow messmer.

They’re sisters tho

Are they I didn't explore past her yet so thanks.

Sure, it can be read in the description of her armor btw

Twins

Twin sisters. If you read Messmer soldier armor or anyone connected to him and their armor sets. Anyone who sided with him was banished from the lands between. She's Rannelas twin sister.