DISCLAIMER: The information here is not all verified yet. Some of the effects may function slightly differently than described here, though the general purpose should be similar in all cases.
Midarian, The Gold Proliferator
The guardian with the golden touch. Rebuild his tower and your dragons might acquire that golden touch too.
Effect: boost gold production by 20% for 1 hour. Can be used once per day.
Jewelem, The Treasure Granter
A guardian with a passion for gems. If you rebuild his tower, he will share his fortune with you.
Effect: 1 Gem per day.
Ramsey, Nourisher of the Eager
Reb uild this tower for its guardian and he will reward your dragons in a delicious way.
Effect: rush up to 8 hours off the Farming time once every 96 hours.
Winstance, The Combat Determiner
Winstance is a natural winner. If you rebuild his tower he shall help your dragons win their combats.
Effect: 20% bonus to HP and damage in combat. The bonus lasts for 1 hour and can be used once every day.
Damona, Patroness of Reproduction
Things in the Breeding Mountain go slowly. Rebuild Damona’s tower, she’ll speed things up for you.
Effect: skip 6 hours of breeding time once every 6 days.
Hanzo is a master in battle techniques. If you rebuild his tower you’ll see how fast learning new attacks can be.
The effect shaves off up to 8 hours of training time, and can be used once every 2 days.
Speedy & Greedy
It’s time to collect food and gold. Rebuild the tower of this guardian and he’ll help you with those tasks.
Effect: Speedy & Greedy will collect (all?) resources in one click, and can be used once every 3 hours.
Broodby, The Birth Watcher
Broodby’s always impatient to see the new dragoonies. So impatient she will even speed up the hatchings!
Effect: It will cut off up to 6 hours of hatching time, and can be used once every 6 days.
Phaun, Sponsor of Species
Phaun loves diversity. Rebuild her tower and lots of exotic species will land on your islands.
Effect: Bonus to breeding rare dragons for 2 hours, and can be used once every 3 days.