A BattleTag™ is a player-chosen nickname that identifies your Blizzard account in our games, websites, community forums, and more. Only one BattleTag can be associated with a Blizzard account.
BattleTag friends are not available cross-region. You must add friends to each region’s friend list when you log in for the first time.
BattleTags do not need to be unique. You can use any name you want, as long as it follows our Naming Policy. Each BattleTag is assigned a numeric ID to create a unique identifier (for example, FallenSlayer#3592).
To change your BattleTag, log in to your Blizzard Account Details and click Update in the BattleTag section.
Note: Each Blizzard account is allowed *one* free BattleTag change.