To find inspiration you watch some episodes of Star Trek, Star Wars, The Expanse and other Babylon 5. You will necessarily play a humanoid character, from there it’s up to you to decide how much you want to physically transform or wear a complex costume.
Keep in mind, however, that if other characters are of the same origin as yours, you will need to get along with them so that your costumes are matched.
In addition, the staff members will wear a short sleeveless gilet with a hood, marking their membership to the Coriphe Church. And all the characters will wear a forearm cuff that needs to be always visible (to be worn in the right arm or left depending on your preference); these elements will be provided by the organization.