Creating believable characters with all kind of motivations, fears, phobias, strengths and weaknesses allow the reader to connect and immerse into the story; It's one of the bigger challenges of writing fiction since its origin, nevertheless is one of the most enriching perks.
There are currently different approaches to the creation of characters; most of them are based on lists where different physical and personality characteristics are specified; these lists simply provide the writer with the discipline to define the characters in his story deeply enough before the writing process as such. The problem lies that some inexperienced writers can fill the data arbitrarily. for example the character possesses characteristics contradictory to each other for example, or an excess of positive ones, creating the typical good character in every aspect (see more on Mary Sue or Gary Stu).
RPGs consist on role playing of different fictional characters by one or more players. They became popular in the 70s with the known system of Dungeons & Dragons and today there is a huge diversity of systems for all types of settings.
Role-playing games focus on the performance of a player in the role of a clearly defined character, and due to the fact that it is a game, there are numerous and strict rules governing the flow of the game as such. This set of rules and characteristics of each type of game is known as a system and is outlined in a core rulebook.
One of the first steps in the role-play is to create the character, and for this, depending on the system, there are a number of steps to carry it out. Usually, it has a finite number of points, which are carefully allocated into a set of skills and attributes by the player. The limited number of points for each section helps the player to prioritize and combine those features in a way that are most advantageous.
An example of a character sheet from a system called Scion (a demigod setting) is as follows:
The first part of the sheet consists of the attributes; physical, social and mental. A strategist, for example, would have a high rate in mental attributes like intelligence and wits; probably accompanied with the social attribute manipulation; and also probably their physical attribute like strength and dexterity would be quite limited for actions such as jumping, running or direct physical fight.
If the character wants to perform an action, such as attempting to hack into a network; It'll require throwing dices to calculate whether the attempt was successful or not; however the number of dices to throw (what is known as dice pool) will be equal to the amount of intelligence points attribute plus points in Craft (electronics) or Science (Computing); so having most points in these characteristics give a bigger dice pool, greater chance of success and even access to more "difficult to hack" networks (higher threshold). Thanks to this carefully defined system, you can develop a story where all the main characters can work together for the development and outcome of the plot.
Apart from Scion, there are hundreds of different systems with their own rules and settings. In the world of RPG there are useful and enriching tools that could be picked and used in the world of fiction writing, such as creating balanced and believable characters with strengths and weaknesses; and even going beyond as to introduce random events and outcomes in the development of history.
Currently, some of these tools have already been used; an example is the famous writer George R. R. Martin who wrote a series of books based on a story initially developed as a role-play gathering with other authors of the saga books. In the cinema world is the case of Vin Diesel in Chronicles of Riddick.
The world of role-playing games and fiction writing has things in common; and in the future, they can grow and learn one from another.