The Edelfelt sisters were considered one Master in the Third Holy Grail, but their unique Sorcery Trait allowed them to summon two sides of the same Heroic Spirit. The Sabers were together for a time, but later served separately under their respective Masters after they split apart. While the sisters were said to be defeated early on, the Saber-class has a reputation of making it to the final battle of the war. The exact details are unknown. The Holy Grail War ended without a victor due to the destruction of the Lesser Grail's vessel. One is said to have been killed, while the other's whereabouts became unknown.
In Lord El-Melloi II Case Files, as payment for Lord El-Melloi II becoming her tutor, Luvia gives him a single Command Spell that her family had left over from when they participated in the Third Holy Grail War. This means that the Edelfelt Sisters held onto at least one command spell after the Third Holy Grail War.
Both sisters normally wear a dress with frills and a choker to match. In hollow ataraxia, both sisters have a dress that goes bellow the shoulders with frills and ribbons, with a choker to match, and brown boots. The elder sister's dress is red and black. In Fate/hollow ataraxia, the older and younger sister appear in the forms of Rin and Sakura respectively , as Avenger cannot recreate them accurately. Their true appearances have not yet been shown. It is also mentioned that the elder sister has command spells on her left hand.
The relationship of the twin sisters was so bad that they set up two operation bases each trip. When participating in the Third Heaven's Feel, the older sister had her mansion built in the forest where the Einzbern castle is, while the younger sister had hers in Shinto. Both mansions were left to the Association after the Heaven's Feel.
During Fate/unlimited codes, one of the sisters was the family's previous head. Luvia acknowledges that this sister was too interested in elegance and extravagance to which she does not share such conceit.
They appear in Fate/hollow ataraxia under the guise of Rin Tohsaka and Sakura Matou due to Avenger being unable to accurately recreate them. Their Servants take on the appearance of Saber and her corrupted self, Saber Alter, and they quickly dispatch Bazett Fraga McRemitz and Avenger during the first loop while they are out on reconnaissance.
They possess the Ore Scales Sorcery Trait, which allows them to share the family's Magic Crest and lineage. It allows them to summon two aspects of their Servant while still remaining as a single Master.