has there been any info if there's going to be any sort of npc "companions" like mercenaries??

No. BUT! There's obviously some of the 'follower' mechanic seen in our gameplay demos: http://www.youtube.com/watch?v=iBKqwdxUH8U

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Q u o t e:

Bashiok can you at least let us know if there is still Hirelings and Followers as announced or if it has been iterated to a different system?

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We're essentially on the same design threads we have been since before announcement.