Need some help here; a few pics from this artist are tagged "吉田サユリ" (yoshida sayuri), but I couldn't find anything on the net, also the pics don't really have much in common between them, the character do look similiar but have different hairstyles/colors/outfits etc.
Seems to be the same (I assume original) character, just with different hair colors on occasion. There are a couple mentions of changed/different colors in the commentaries.
