"Do you have any way to identify her? If my guess about the population of that heavenly city or something is right, then even locating her might be akin to looking for a needle in the haystack."
Finding someone in a big city, wasn't that hard. Doing so while trying my best to appear like any other cultivator of their technique, without even a single clue how higher stages of it have worked, was the hard point of this task.
If I were to judge the most inhabitants of the Overlord's island as the low levels, the elder that attempted to kill me and even managed to scratch my face as the medium stage, and someone even stronger as a proper high level… Even without the system upgrade, fighting them wouldn't be that much of a challenge!