Shirley Fenette was no longer as she was basically dead at this point. Her entire existence was replaced by the humanoid Knightmare frame that she had become called PXSF-001. However, they also had what was considered an alias or codename that she had accepted from Julius directly being Angel. It was not one that was formally given but it was accepted by her as such and no attempt to remove or change it could be done once that happened. This was seemingly considered a designation given to her directly by Julius who she was to serve thus she accepted only that as his alias. When called by anything other than her name or her alias she would not respond, claiming that she was being spoken to. As both ways to refer to her were well known thus they should be able to recall what they were in order to do so. This while seen as somewhat flawed in the process was then just considered a quirk of it instead. After all PXSF-0001 or Angel followed all orders that she was given by Julius and was following his every command after all. They just assumed that she was loyal to Britannia because she did this.
It was discovered that other quirks beyond the one that existed that caused her to just accept Angel as he alias because Julius just called her that once. Existed however were overlooked because they were stabilizing the current persona causing it to take root more deeply and convince Julius that his current life and existence is his proper one. With Charles' geass was used in a similar manner to how he made everyone that knew about his daughter Nunnally vi Britannia forget about her. People were made to forget that a person called Shirley Fenette ever existed in the first place. However, thus the more human form that Angel could assume while looking similar to Shirley was different as well. Since Angel's hair color in her human form matched the primary color of her true form with her eyes now being the same color as her true form as well. These were different from what they were when she was originally human thus making her seem like even more of a different person as the hair color change was not caused by dye and contacts but now considered her normal 'natural' colors.
Cementing her existence over Shirley even more as the mere idea of people called Shirley and Lelouch was becoming less and less solid. With fewer and fewer connections existing to prove that they were the real and not just dreams that Julius has from time to time. Further, the goals of Charles to use everything that Lelouch had managed to do for his own means as Julius thought.
Yet Shirley was convinced into a humanoid Knightmare not to serve not as the means to stabilize the false persona of Julius Kingsley or Lelouch vi Britannia. She was done so because a unit that could have all the powers of a Knightmare but fit into the human size area was desired. Traditional Knightmare while they were a game changer in war and combat their size was something that did limit their usage. Being nearly twenty feet tall would of course limit the place that you would be able to get to and around with ease. There were not many places thus why this normally was not an issue however they did exist and if a smaller more human size Knightmare frame existed then that problem would be solved. Thus why and how Angel now existed as the first successful humanoid Knightmare frame as. It was decided to just turn humans into them rather than just make them from the ground up like traditional Knightmare frames were.
However, what Angel excelled at was limited to long range combat only as she was lacking in both close and mid range combat. Of course, there was no way that normal humans would outmatch her in either but Charles and the others that developed and funded this project. They were well aware that humans existed that were far beyond what you were consider normal but in the traditional sense and the supernatural sense. After all, they were being led by someone that had Geass after all and there were bound to be other powers like it or similar in the world. Thus while Angel could possibly dominate the battlefield in the normal sense keeping her where she specialized that being long range was decided on by Julius who was now considered part of the project as he was to lead a strike unit that would be composed of humanoid Knightmare that were all under his command and following his orders. The first of them was PXSF-001 that would serve as the long range specialist as such she did not need to carry any weapons with her normally.
She could manifest various guns at will that would fit her purposes to whatever goal she was aiming for. Though manifest is merely her taking a gun in question from the place where it is stored within her own body. As for how she was able to store all these guns within herself and even supply them all with bullets as well. That was just all part of her design it seemed as if her core that being her miniature Yggdrasil Drive was considered to be how she was pulling this all off. As the a Sakuradite device called the Core Luminous that also plays a role in all this as well. It was currently unknown how she would need to recharge as they do not know currently of any location where the Sakuradite Energy Filler can be placed on Angel at the moment.