To participate in the current Season, you'll need a Seasonal Hero. To create one and begin your new adventure, simply select the "CREATE" button on the Hero Selection screen. Make sure to mark the "Seasonal Hero" checkbox and then select "CREATE HERO". Seasonal Heroes start off with a blank-slate. They have their own shared stash and, until the current Season is over, they may not access any non-Seasonal items, materials, or gold already present on your account.
Diablo III's Leaderboards can be accessed from the main menu by selecting the ladder icon on the bottom right corner or with (SHIFT + L). Leaderboards allow players to compete for ranked achievements with others—within the same region, clan, friends list, class, and with other parties of players. The Rankings page will also let you track player statistics.
Player progress in Greater Rifts is ranked by highest difficulty, and fastest time within that difficulty. This Leaderboard tracks statistics for both Seasonal and non-Seasonal Heroes.
The Season Achievements tab will rank the highest character achievement score according to who earned it first. The total score includes all normal achievements earned during the current Season on top of extra Season Only achievements. To participate, create a Seasonal Hero and earn as many achievements as you can before the current Season ends.
The Conquests tab keeps track of players that have first completed Conquests in the current Season. It can be filtered by the first 1000 players within your region; by friends and by clan mates. Conquests are much harder to complete than regular achievements and the Leaderboard for them resets each Season.
In Seasons, you’ll be able to earn cosmetic items to add to your Collection; Pets, Portraits, Wings, Pennants, and more.
At the end of each Season, all Seasonal Heroes will be moved over to the existing non-Seasonal Hero pool. All items, currency, and materials obtained by your Seasonal Heroes will be made available to your regular Heroes. Items that were in your Seasonal stash will be sent to you through the in-game Messages system. To participate in the next Season, you'll have to create a new Seasonal Hero and start your journey anew!