Gems

Gems are one of the currency in the Timing Hero.

Advice with earning and allocating gems
There are multiple ways of acquiring and using gems while playing the game.

Acquisition / Earning Overall the game gives you enough gems to get by. Though at the very start you'll be likely to be slightly strapped for them. The amount of gems you can earn daily, as shown above.
 * 1) Defeating bosses in Campaign mode : Early bosses don't offer much in the way of gems but running a character from level 1 through to level 120 will earn you about 60 gems. From that the total gems you can acquire from the campaign are about ~1700. Though the effort taken to do so would be prohibitive.
 * 2) Daily gem bonus : Increases as time goes by. when you reach the end you actually get the final bonus for every day you log in after that. So, 20 per day you keep it up.
 * 3) Raid : In raid, you will earn gems as one of the random rewards, a day through the raids may earn you anywhere from 3-20 gems.
 * 4) Video rewards : There's a not so surprise video reward that gives you 1-5 gems. It's a daily reward so watching 50 videos isn't likely to give you multiple dips into the pot. But there's likely to be a timer on it as I've found that occasionally if I log on later in the day you can get a second reward.

Expenditure / Allocating Despite the convenience of this, its main purpose is likely to finishing levelling up your artifacts once you've unlocked all the slots.
 * 1) Unlocking Characters : The second most important expenditure of gems would be unlocking characters, the sniper and the 70 gem character in the melee tree are both potentially worthy unlocks while waiting for the Colosseum cards to be earned. But once you have the Warchief or the Plumber, unlockable classes get outclassed heavily.
 * 2) Unlocking artifact slots : You can unlock up to 15 artifact slots. however, the gem cost increases with every artifact slot unlocked. (Up to 300 for the final one I think). These slots aren't enough to get every artifact so it's important to make sure you think long term about the ones you unlock. Increased Crit chance against bosses and Increased counterattack chance are 2 essential ones to the max as it eventually helps you with being able to permanently ability lock raid bosses.
 * 3) Purchasing credits : Probably an endgame only expenditure which is very helpful before level 70 on attack and health, level 40 on crit and around level 15 on health regen. Gems can be traded for credits based on the character's level. This is significant as if you spend 1 or 2 gems to level up health and attack at the very start the number of credits a gem gives you jumps up massively.