Traitor.
Trapped inside Atropos' Limited Rift, Nino was left with only her Yari.
The blue box was practically a minuscule pocket dimension isolated from the rest of existence. It blocked access to every external dimension that's required for the use of several runes, including the 23rd dimension from which they draw the Nameless Element and the 45th which is the source of Balder's Light.
"Great, don't you think?" Atropos said, raising her sword to shoulder level as she took a stance. "Now no one can interrupt us, and you can't use your little tricks. It will be a fair duel just like back in the day."
Nino was in no mood for talk, having already determined herself. One strike was all her sister needed to finish the fight. She, on the other hand, would have to do a lot more.