Of those people, those who have completed it faster will get a higher rank. The highest rank is awarded to the player(s) who have successfully cleared the highest rank of a Greater Rift on time. But rebirth is just a handy with to delete and re-create character. Alternatively way is to rebirth existing character as Seasonal. All seasonal characters start at level 1 with (almost) no gear. Make sure you check the Season checkbox on the character creation screen. top players for Barbarian, Demon Hunter, Crusader, etc.) You need to create a new Seasonal character (s). To help encourage a variety of play styles and allow players to measure themselves against similar competitors, Greater Rift leaderboards are broken into the following categories: Greater Rift Leaderboards are split between both Hardcore and Normal gameplay modes as well as Seasonal and Non-Seasonal characters.

Each type of board tracks progress differently: Greater Rift Leaderboards Leaderboards allow players to compare their progress to that of your gameplay region, friends, and clan members. Leaderboards keep track of progress made in Greater Rifts, Seasons (and seasonal achievement points), and Conquests.

Diablo 3 barbarian leaderboards