EnoYls gives on WoW’s forum interesting informations about Blizzard North. One of the two divisions of the company:

Blizzard North was formerly a company known as “Condor”. During the development of the original Diablo they were acquired by Blizzard and dubbed Blizzard North
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All the development teams at Blizzard and Blizzard North have created their own game engines. However, both teams consult quite a bit with each other and share information to make both team stronger.