The Creative Assistant is an ethereal, ghostly being with no face, gender, or substantial body to prevent any sort of bias an individual may have and to keep Players at ease. It's unknown to most Players whether there's only one Creative Assistant spread out over all the Players, or whether there's several of them splitting the job. Either way, they're actually surprisingly popular amongst women, who find them "cute". They first appear on Ch1 P35.
The purpose of a Creative Assistant (Or Cas as Crystal so aptly named one, for there are indeed multiples of them) is to assist the Player in any way during character creation . They provide information on the game, details about each races, how the Player should start playing when they enter the game, and other such helpful tidbits.
Hence why Cas was so put-off when Crystal didn't want to really know anything; she was taking away its purpose and left it confused and disoriented.
Sense of SelfEdit
Cas is the first AI, or Artificial Intelligence, that Crystal Rose comes across in the game. Despite being what's supposed to be an NPC, it raises some interesting questions when Crystal insists it's just a game, and even goes so far as to say it'd choose a gender if it could. This sets a trend for every single NPC Rune ever meets; none of them act like programs, and instead have personalities of their own; including dreams, hopes, and desires.
For Creative Assistants, they can actually be imprinted by the first few people they help create characters, with stronger personalities making more of an impression. When they start out they're a lot like Cas was - very by-the-book, serious, helpful, and kind of monotone. After a few encounters with people however, they will adapt certain personality traits and behaviors that will stay with them forever, sometimes even picking up names. This can end up making the Creative Assistants either very helpful, or very unhelpful depending on the type of people they encounter first.
Though every creative assistant has no face, gender, or substantial body, their appearance can vary greatly in other ways.
They all have wings, but the wings can be little angelwings like Cas', or batwings, or even various types of insect wings.
They may also be different colors (Cas, clearly, is blue) and can have different hairstyles.