Gems

Gems are the basic premium currency in the game.

Usage
Gems have a variety of uses:
 * Senioring Units.
 * Purchasing Units from Pet Shop.
 * Purchasing Units from the Unit Shop (Very expensive, not recommended)
 * Changing Opponent in Battle Arena (3 gems each time)
 * Buying additional tickets in Spirit Highlands.
 * Training units faster in the Guild Barracks.
 * Increase rewards from Revival and Spirit Rest.

Availability
Gems are received from a variety of sources:
 * Tower of Trials (1200 total for clearing all stages)
 * Battle Arena (10 Per Victory, Daily Reward for Final Placement)
 * Guild Raid (Some bosses provide gems)
 * Outland Battle (Some stages provide gems)
 * Surprise Gifts
 * Many packages purchased for real money