Indigo Berry

timekeeper encouraging blueberry to use the forbidden powers .... see what could be achieved, show her countless futures-- and how many of them are lonely, endless silent nights waiting for the moonlight and wizards that never come back for her

maybe its even because of who she is, "blueberry pie" has never fit in with the mystic stars and moon, nothing of the power or knowledge the wizards worked for timekeeper shows her countless futures, and with timekeeper's encouragement eventually she reads everything in the restricted section, then going on to try to attain the power of the stars for herself, during this is when she slowly at first then, experiment after experiment, she crystalizes into Star Sapphire Cookie of course, timekeeper is there for her, helping her to not shatter and die under the strain of everything she's done and learned. she realizes she is exactly what she wanted now: a cookie based in the stars, but it came at such a cost even more, she realizes that despite the small amount of stardust in her dough now, she's a gemstone which can only be from earthbread and she got both infinitely closer and further from what she wanted

she returns to the archives from. wherever she went. and its in disarray from her unleashing the restricted section she somewhat cleans it up, but makes the archives and city of wizards even more inaccessible from the outside, and kind of "takes over" the city but she doesn't do much she just stays in the archives, trying to cope with all the knowledge and trying to find a way to make herself really one with the stars (in a way, its like dark enchantress but a lot less people die)

so blueberry pie cookie becomes star sapphire cookie!! her design is based off the blueberry "drops" crystalizing and becoming star sapphires (sapphires with the asterism phenomena) she'd have time-based accessories because influence from timekeeper, some gold probably as well as a lot of gold lines in her blue outfit (which are meant to represent rutile silk inclusions that can be found in sapphires)