Hello, I'm a wizard. I get excited about situations where a girl wants to transform herself into a strange body, and that's how it feels for Moro this time.
The combatant who appears, Special Agent Venom Soldier No. 185, has already been brainwashed and is imbued with the organization's values, so he volunteers to perform the modification surgery himself. Personally, I think it's great when these plain girls are brainwashed and go on a rampage as if they've been freed from oppression, or when their kindness turns into a cruel, false character.
As always, the text is thought of haphazardly based on the context, but it seems that the hierarchy of monsters within this organization is high, and it seems that phantomization surgery is not available to everyone. In that case, she was chosen as the subject of the monster-making process, and it's possible that she achieved something special. For example... he infiltrated the school of his enemy, a magical girl, and succeeded in gaining her trust as a friend. If so, what was the magical girl's reaction when she saw her changed "friend" in front of her? And you might enjoy it more if you fantasize about the crafts that No. 185 was doing on the magical girl pretending to be her friend ――like crafting transformation items, making subtle hints, or giving her special bodily fluids to keep her from being noticed――.