There are 3 main statistics in Ragnaros.
Strength- Strength is used for physical attacks used in the Aggressor and the Safeguard classes. It is used to calculate how strong physical attacks can possibly be.
Magic- Magic is the same as strength only used for the Liquidator, Alleviator, and Attenuate. Magic is used to calculate how strong magical attacks and healing spells can possibly be. For the Attenuate 1/10 of the magic statistic is used as damage when debuffing the enemy.
Defense Percent- depending on the choices of the players, some character will have higher defense percent than others. With defense percent, you use this percentage to calculate how much less damage you take from enemy attacks and spells. Defense percent can be increased through the Safeguard class and through Accessories. Note, some spells negate defense percent.
Dexterity and Resistance.
Dexterity is determined with the d12. It is solely raised on Accessories alone. All players start with a 1 out of 12 chance to dodge any enemy attacks.
Resistance is determined the same way. Only it uses a d8 instead where characters have a 1 in 8 chance of resisting all status debuffs. Resistance can only be brought up with Accessories as well.