There is one EULA for all Blizzard games and services. This includes the launcher, forums, games, and mobile apps.
This is their currently released statement. It is tagged for WoW, but usually Blizz has the same policies across games.
Blizzard Support - Multiboxing
Multiboxing, or playing multiple World of Warcraft accounts at once, is not a violation of our End User License Agreement. Please note, however, that use of all software or hardware mechanisms used to mirror commands to multiple World of Warcraft accounts at the same time, or to automate or streamline multiboxing in any way may result in account penalties.