Realms is a system created by gamers for gamers. Realms allows more customizable characters, items, creatures, NPCs and worlds. With an expansive list of skills and spells Realms does not limit a character to skills built around a class. A warrior can take mage skills and a mage is able to take skills allowing them to wear heavy armor and wield a sword.
The number of playable character races is as variable as the composition of the player. The spell and skill progressions are a point system based on the path chosen by the player. There is also a correlation between the skill levels and character levels, but one does not determine the other.
Most dice rolls are based on the results of a roll of percentile dice.