David Gaider - Design, Bioware corp. -
XP Storyline (Spoiler Warning!):
(ED NOTE: *******MASSIVE SPOILERS AHEAD*******)
Okay, fine. Since I'm tired of seeing these questions, I'll just explain it.
You don't know Drogan is a harper. You also know nothing about the artifacts that he's hiding. You're at Drogan's school (or home, rather... it's not really a school except that Drogan has several students) as his most senior student taking advantage of Drogan's many years of experience as an adventurer, though it's left indeterminate as to exactly how long you've been there. It's also left up to the PC in the course of the dialogues to establish the relationship he/she has with Drogan.
You don't find out that Drogan is a harper until after the events at the start of the module when another harper shows up to help. That's also when you find out about the artifacts, and yes... you have the option of keeping them for yourself, if you wish. These artifacts have never had their exact use figured out (only the fact that they have great power is known), so the harpers are more interested in keeping them out of the hands of this mysterious enemy than wondering what you might do with them.
I guess the people who wrote the article didn't want to go overboard on the spoilers by explaining all that, but there you go.