A comment here suggests that
Whenever you kill a boss for the first time (on normal difficulty
only), it is guaranteed to drop at least 2 rares: One general rare and
one specifically suited for your class
Is this true?
I'm fairly sure I didn't get anything but blues the first two times I killed the Skeleton King (although my friends got yellows), however the Spider Queen, the Butcher, and Maghda all dropped me two yellows. I can't remember if one was class-specific in all cases, however it was true in at least some cases.
Edit: I've verified that the Skeleton King does not always drop two yellow items, and am trying to determine if A) this quote is correct, incorrect, or partially incorrect and B) if correct or partially correct, does this only apply to end-of-act bosses?
Best Answer
It's true... sort of.
The rare drop rate is substantially higher for first time kills of major bosses on normal mode, but it isn't necessarily two drops guaranteed - the specific bonus and which bosses it applies to hasn't been laid out explicitly. For what confirmation does exist, see this post by Bashlok:
Whether the 'bonus to drops' is 'guaranteed class-specific yellow', or simply 'twenty percent increase to the chance to drop' is unclear, and without a very large data set or some (very unlikely) additional candor on the matter from Blizzard, it's difficult to say. Anecdotally, people seem to be citing the '2 rares, one for your class' fairly widely, and I'm yet to personally have any experiences that contradict that - at least on major bosses. If I had to guess, I'd wager the Skeleton King doesn't qualify as one however.