League Credits is one of the currencies in Injustice 2 Mobile, earned through activities of Leagues. It can be used to purchase hero shards and gear for 4 exclusive characters as well as all 5 types of specific tier 6 xp capsules.

Hero shards (5) OR Gear Price
Atrocitus 300
John Stewart Green Lantern 100
Power Girl 100
The Reverse Flash 200

There are 3 sets of 5 hero shards for each character, as well as 5 pieces of gear for each piece in stock.

All tier 6 xp capsules cost 50 League Credits each, with 20 of each in stock.