Possible end of the world shit. It wasn't the first time the Black Widow had gone up against that type of opponent, but the tearing worlds apart comment did cause her pulse to quicken. She'd gone through hell and back to defeat Thanos and she was honest to God terrified to do it again.
Not that any of this showed in her physical demeanor. Her weapons stayed trained on Sephiroth without even a trace of wavering She gave a nod when Crossfire landed on her other side.
"Seems like."
She did notice that Sephiroth hadn't moved or reacted much in the time the three women arrived. Which was absolutely out of the ordinary, in her experience. He seemed fairly stunned himself by...something. Whether it was his arrival or something else entirely, she didn't know.
"Hey." Natasha called out sharply to him. "Drop your weapon now."