Characters have names, gender, attributes and must choose a class. All of those are set by the player at creation time. Also, when a gender and a class is chosen, a predetermined gender specific portrait is assigned to the character and the colors can be customized to the player's liking.
Characters wage battle against monsters and gain experience by winning those battles. After time, it increases the character's experience level, granting skill points and making it stronger by increasing its health for example. Also, depending on the character's attributes, some game variables will change ( for example, the character might deal more damage or be more capable at hitting it's target ).
Every character class has a special set of unique skills that can be used in or outside combat. Every skill has a level and a player can increase that level by assigning skill points to it. By doing so, the skill becomes more powerful and can even unlock new previously unavailable skills.