Mortal Kombat 11 Currencies Explained: Koins, Krystals, Kredits, and More

Koins are the most basic currency earned by playing any mode. They are used to activate the Dragon Shrine for rewards.
Dragon Krystals are premium currency bought with real money. They unlock cosmetics and Easy Fatalities.
Seasonal Kredits are earned through Towers, Online, and Quests. They buy seasonal/themed cosmetics in the Store.
Krowns are exclusive to the Invasion mode. They are spent on boosters and gear upgrades.
Playing matches, completing modes, and leveling up earn you currencies for different purchases.

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Relevant topic timeline:

9/21/2023

Mortal Kombat 1 Offers Paid Unlocks for $8-20 Alongside $70 Base Game, Despite Praise as Best Since 2011

Mortal Kombat 1 introduces new options for players, including the ability to skip unlocking characters through grind and instead purchase them with real money.

9/25/2023

Mortal Kombat 1 Tops UK Sales Chart as Lies of P and Pikmin Make Strong Debuts

Mortal Kombat 1 tops the UK physical game sales chart in its debut week, with the Nintendo Switch port only accounting for 7% of the game's overall sales.