When a new player starts to play ranked games, it is from the Novice league. The characteristics of this league are that the rating doesn't drop when losing a battle and that one doesn't earn rewards when playing in Novice. Rewards only start in Bronze, and only after buying the Summoner's Spellbook, which costs $10 USD.
There are 6 leagues in the game:
Each league, starting from Bronze upwards, is divided into 3 sub-leagues (or levels), like this:
- bronze III
- bronze II
- bronze I
with bronze III being the lowest league and bronze I the highest league.
The highest league in the game is Champion I. For that, one needs at least a rating of 4700+ and 500,000 collection power for the wild format or 250,000 collection power for the modern format (half of wild requirement).
For example, if one finishes Modern in Gold I and Wild in Silver II, one resets the new season in Modern from Silver I and Wild from Bronze II.
Resetting for bronze players is a bit different since they don't have 3 leagues below. From Bronze III reset is Novice, while for Bronze II and Bronze I, reset is Bronze III, but with different starting ratings (100 and 300).
For the daily focus loot chests, what counts is the highest league between Modern and Wild at the start of the daily focus mission.
Each league has a leaderboard with special prizes for top-ranked players in the league.
When players reach the threshold to advance to a higher league, they have the option to move higher or stay in the same league and play for the leaderboard.
Because of the way the rating fluctuates, it is quite difficult to grow it once one stays in the same league and has a higher rating than most opponents.
See also League Caps / Limits.