2/ They say you can team-up with an NPC. When does it occur ? How does it work ? Is it similar to D2 ?
There's an option to near the start of the game, but it is only temporary and (in my opinion) not of great benefit. There are also summonings that you can bring along with you.
Hi !
Please explain : "....There's an option to near the start of the game"
What do you mean ? During gameplay or is it an option on the main menu?
True, I don't really need it but I'm just curious about Hirelings.