Mortal Kombat Mobile have seven different types of currencies. All these currencies are used in game to purchase different items, like characters, equipment, energies, and multiple other cards. in this article I am trying to explain each one by one & also, tell you, how to earn these currencies in MK Mobile game.
1. Dragon Krystals. 
Dragon Krystals is used to acquire high value content in the Dragon Krystals store.
You can earn these Dragon Krystals as an elite reward from multiple game modes. like challenge mode, faction war weekly rewards, Tower’s final match rewards, The Krypt mode and they are also, earned when acquiring duplicates of high value max fusion content (I mean from resell character’s & equipment’s)
The amount of Dragon Krystals that can be earned via duplicates (resell) is limited daily.
2. Blood Rubies. 
Blood Rubies can be earned by playing Faction Wars. At the end of each season, you can earn Blood Rubies to spend on exclusive cards in the Faction Wars Store. Blood Rubies can also be earned from Shao Kahn Tower, Relic Hunt Event and daily task. Unspent Blood Rubies will carry over from season to season.
3. Koins. 
Koins are used to upgrade Characters, Abilities, Supports, and to buy offers in the Store.
They are earned from Daily Objectives, as rewards from multiple Game Modes battles, like, challenge mode, faction war, Tower’s, special events, battle mode and Quest Mode. Resell character and equipment also give an amount Koins or We can be purchased in the Store with souls.
4. Souls. 
Souls are used to upgrade Character Passives, refresh attempts in several Game Modes, and to buy offers in the Store.
They are earned from Daily Objectives, as rewards from multiple Game Modes battles, like, challenge mode, faction war, Tower’s, special events, battle mode and Quest Mode. Resell character and equipment also give an amount Souls or We can be purchased in the Store with Real Money.
5. Runes. 
Runes used to purchase packs in Feats of Strength to acquire more War Banner and characters customization options. They are also earned when receiving a War Banner that is already owned.
6. Krypt Keys. 
Krypt Keys are used to enter the Krypt beyond the Daily Free Attempts that refresh. They can be found within the Krypt, junk box and occasionally from other game modes or purchased in the Store with real money.
7. Krypt Hearts. 
Krypt Hearts are used to purchase Characters, Equipment, Junk Box and Konsumables within the Krypt Store. They can be earned during a Krypt run.