Neo encountered her in the Merovingian's Chateau being tortured by some of his henchmen. After he defeated her torturers she used her banshee like howl to free herself from the chains, insisting she had it under control but commenting on his good timing she ran on towards the exit.
Neo encountered her further in the Chateau being attacked by Insectoids which she asked him to destroy, telling him of their vulnerability to fire and leaving him to it, and again when stuck outside a locked gate she needed him to open.
He found her captured once more after fighting through Club Hel and making it to the Merovingian's most powerful Exile: the Witch. While set up as a test along with two other physically identical Witches, Neo could distinguish her from the others by their code; her unique blue code contrasting with their red.
After saving her from being crushed by a block above her poised to fall, he proceeded to attack the Witch who used her powers to displace and hurl pillars and other objects at him, teleporting the Rogue Witch next to herself when Neo got too close to her, causing the Rogue Witch to scream and knock Neo back, or teleporting herself away.
After being badly hurt the Witch changed tactics, using a bo staff and causing a disruptive vortex to appear around her, which the Rogue Witch stopped using her howl, proceeding to attack the unprotected Witch along with Neo.
Towards the end of the fight she began to tear down the room with her screams, and once the Witch was defeated she blasted a hole in the wall, revealing a door which was the final exit from the Chateau. As Neo left she said she would go her own way, but that they would meet again.
Based on the legends of witches and banshees, she could break out of chains, knock people off their feet and daze them and even tear down walls solely by screaming. Her code was also uniquely blue rather than the normal green, or red for other witches.