Life's greatest strength lies in their archers and thieves. Both have the longest range and highest attack of any on Urak. The warriors have good defense, and the mages can heal their wounds in combat. The Pegasus is a great wall in front of your archers, and will last for some time. Use a combination of all these to take control of the land.
The Elven Warlord - This lord has great defense, ranking the highest of all. His attack though, is the lowest of all. You'll need some artifacts to increase this. Use him like any other lord, and defend self while your archers take them out.
The Elven Thief Lord - This lord is the best of all the thieves. He has the highest ranged attack and longest range. He is great at sneaking around and taking out attackers from behind.
The Enchantress Lord - She is very difficult to start with, and doesn't get a whole lot better. She cannot come close to taking over any structures by herself, making it difficult to gain levels. Her only good spells are to help others, and to heal them. Ray of Hope, the best attack spell, isn't much better than justice, and it costs more mana.