The Black Knight worked to get Rex as her copies worked on the others. If only because the power Rex could have once she altered things and re-activated the Meta-Nanites. The first step was to alter reality so Rex was alone without anyone close by. Then made herself appear in front of him suddenly.
Rex moved back in shock as he saw her, "Black Knight? I thought you were rocking the mecha-knight form last time we saw you? How did you get here?"
She looked at him, using the power to alter reality, to see into his mind. A plan formed, "Rex, we don't have to be enemies. We can be friends. Bury the hatchet. Forget the past!"
With that last phrase, she did a few things. Trigger amnesia. Just as Rex had amnesia in the past from losing control of his powers, losing all personal memories. She had also noticed his personality changed when he lost his memories, being influenced by those around him. Which was why she gave him new memories beginning with a previous mind wipe. Instead of the truth of being rescued by Agent Six after losing control of his powers, he now remember being rescued by her.
'He will now remember being trained by me, of my showing him of his true potential, winning his trust by showing him our shared powers and histories, and replacing his crush on Dr. Holiday with a crush on me.' she thought as she edited the history using real events and events which benefited her but didn't happen.
'He remember being my agent in Providence and among White Knights team. Of gathering the Meta-nanites for me, pretending he shut them down but kept them active, and... being my loyal and devoted lover. Sex being an excellent control over men, and he is handsome as well as being an excellent asset for my... stress release.' she thought as she made some changed as well to Rex, including turning his trademark red jacket to her shade of black.
Once she completed the changes, she woke him up, as he looked at her differently. No longer looking at her like a threatening foe, but as a lover, "My Black Queen, what can I do for you?"
"Just came to see you again, Rex. Wanted to hear you say you're mine again before spending time with you." she asked him, wanting him to become hers so she could win this contest.
"My heart, mind and body belongs to you, mi amore." he said as he moved to embrace her, which she welcomed in her victory. Cause now she had one of the most powerful men in the world at her service, along with the god-like power he held.