What currency is used to unlock champions with gameplay?

The currency used to unlock champions through gameplay is Blue Essence.

Blue Essence is League of Legends’ main free-to-earn champion currency. Players can accumulate it by playing matches, completing missions, and converting certain rewards or champion-related loot. It is spent in the in-game store to unlock many champions without paying real money.

The system replaced Influence Points, the currency used during League’s earlier years. That change is the source of one of the most common mix-ups: Influence Points is a historically correct name for the old system, but it is not the current standard answer. Blue Essence also replaced the former champion-shard disenchanting economy in the modern reward structure, while champion shards can still affect how players unlock or discount champions.

Blue Essence is different from Riot Points, which are purchased with real money and are primarily used for cosmetic content and other premium purchases. Gold is another in-match currency, but it buys items during a game rather than unlocking champions permanently in the account store.