Trolls
The Troll race can be used with the Shaman or Nature class. Picking Trolls will automatically give you a +5% attack and +5% defense bonus

Ogres
Ogres can be used with Nature or Necromancer classes. Choosing Ogre gives you a 10% mining and 10% speed bonus.

Humans
The Human race can be used with Druid, Magi, Necromancer, or Feudal classes. You will receive a 10% taxation bonus for this race.

Elves
Nature, Demonology and Druid can use this race. They will receive a +20% lumber bonus.

Goblins
Nature, Demonology, and Magi classes can pick this race. They receive a +25% Population Bonus