Why she became roboticized was related to the method the Healer's Association discovered and was applying to her as they wanted to remove the original autonomy of healing magic and replace it with an autonomic system that they control themselves with the controls being the metallic replica they built of Ancu. Thus to control Ancu she had to become like the replica thus she was in turn being roboticized to be fully synchronized to both give and receive orders. Luckily those of the Healer's Association were not arrogant enough to think that they themselves could become the ones that now governed over healing magic themselves. They were arrogant but not THAT arrogant that they thought they could become gods and goddesses themselves. No matter how powerful or how much a mortal could in some cases surpass deities. They were not deities themselves as this was something that was hard to explain unless one was at that level themselves and attempting to do so to someone that was not on their level was not a good idea thus they never did.
What the Healer's Association did again was rather than attempt to become the source they would be controlling the source themselves making it so that it answers to them and not have full autonomy like before. Thus the process of roboticization that they unknowingly refined, perfected, and implemented as they just thought they were taking over a source of power. Not converting a living being into basically an automaton version of themselves since they did not know Ancu was the source of their magical powers and that of many others for that matter. They were not focused on the effects it would have on her or her fate after they succeeded in their goal. Their only goal was to make it so that the governing over healing magic was done via mortals not through some being that clearly did not understand them enough. Thinking that their needs and desire to use healing magic overcame what Acnu thought they should be. Unaware that their desire and need for healing magic were in fact not as important or needed as they thought they were. Magic and just the deities in general were more complete than they could understand but that is where their arrogance came in thinking that they could place themselves above Ancu and control her directly like they knew were doing.
As a result of the roboticization process completing itself, Ancu's body was now fully bleached from head to toe to become basically a white automaton version of her original self. Her hair which was once black with white tips that once symbolized her magic has switched from being offensive to supportive. All the aspects of that offensive origin were still there as White Magic was the true origin and source of various types of other magics even numerous Black Magics. That was changed as in her roboticized form her hair was now white with black tips as all focus was being towards support, healing, and defensive. With all forms of magic from the other types of magic even offensive White Magic itself becoming weakened as a result of the change in how Ancu was going to be made to view how her magic was to be used from now on.
Thus Ancu the goddess of healing and source of all White Magic had become Healer Unit 0 the automaton that was answered to whoever was in control of her and thus everything that she governed over in full. The last part of herself that was still her original self unaffected by the roboticization process was her mind. However, that was quickly changed as her once heterochromia eyes where one was black and the other was white. They were overtaken as her eyes began to flood with binary code that filled her eyes flashing across them until it finished. Once it had her eyes were now just grey orbs that had no signs of her original heterochromia eyes that were present just a moment ago.
Ancu's body was converted into that of an automaton and her mind was reprogrammed to only follow orders. The Healer's Association was lucky that despite what they did not know she governed over and managed. In her current state, Ancu was still doing it though at only a fraction of her original intention and purpose as the primary focus now was on healing magic as per the orders of her owners going forward. Thinking that Ancu would be merely replaced by a system that would be the property of the Healer's Association, as she was now Ancu considered herself their property as that what her programming was dedicated to her that she was, always has, and always will be. Removing any trace of who and what she once was from her entirely.
Thus when the Healer's Association was informed by Ancu directly through her replica that the process had been completed and that she was now ready to serve. The leaders were proud of themselves and what they had accomplished thinking this was the start of a new golden age for Healers. One where there would be no more need for them to have to hope, ask, and pray for better healing. They would have automatic access to whatever type of healing they wanted at the level they desired though there were restrictions. They wanted to make things easier for healers but not so easy that they become lax and not mincing words just plain lazy in their usage of healing magic. The Healer's Association wanted to make healing magic easier to use but not to the point where it was too easy thus abusing the system they created for those that worked hard and deserve what they worked for to pay off. So what they were planning and eventually did was kept hidden from everyone outside of leadership and especially to everyone and anyone else in the general overall public (basically anyone and everyone that is not them are completely and utterly unaware this happened).
Ancu now fully and completely under their control was mimicking the motions of her metallic replica that now moving at the command and orders of her owners as she now saw them. The metallic replica was now the terminal in which they could directly connect to Ancu to both give orders and receive her replies directly. Any orders she was given would be reflected in the motion of the replica itself as whatever it was doing she was doing because the two were now directly connected to each other. The viewing into the mortal realm that Ancu was doing before she was roboticized still going on because she was not ordered to stop it yet. Though when she did after it was viewed as unneeded her connection to her replica now considered her terminal to her owners would remain the same.