Eternals are League of Legends’ version of stat-tracking achievements and have been a part of the game since 2020. While each champion has a common set of Eternals that track your general progress in-game, champions also have tailor-made sets of Eternals that track specific achievements you can unlock.
Eternals have even more purpose, as they’re used to complete specific challenges introduced to the game’s client in 2022. Some of the most notable Eternal-related challenges can be completed by “rekindling” an Eternals set. These challenges take time and require playing games with a specific champion.