In addition, whenever a marked enemy that is
adjacent to you shifts or makes an attack that does not
include you, you can make a melee basic attack against
that enemy as an immediate interrupt.
You gain a bonus to opportunity attacks equal to your
Wisdom modifier. An enemy struck by your opportunity
attack stops moving, if a move provoked the
attack.
inati,
I think you're missing the difference between an OA and the immediate reaction basic attack granted by the Fighter challange.
inantiIn your scenario said:shift[/B]. This activates Combat Challenge (ref above). Since Combat Challenge is an immediate interrupt (also above) it is limited to only once per round, as per the rules, so he would get to smack only one creature, even if they all shifted.
Now if the kobolds had all moved, this would draw an Opportunity Attack, which is once per Combatant's turn. So as each kobold moves, it would be hit by an Opportunity Attack, which activates Combat Superiority./quote]
Emphasis mine. You missed that inanti is describing two scenarios, one in which all the marked kobolds shift, and one in which they all move instead.
Another reason why the 9 opportunity attacks doesn't work is because you get only 1 opportunity attack per TURN. The goblins aren't shifting on their individual turns, they're shifting on the FIGHTER's turn. So if a fighter makes an attack and for some odd reason forces multiple enemies to open themselves up to AoOs (which isn't possible, as outlined above) he could only choose one of which to make his OA on.
Note that inanti's example uses kobolds, not goblins. Kobolds shift as a minor action on their turn. Which is a moot point anyways because inanti is talking about opportunity attacks, not Combat Challenge attacks, which are provoked by moving, not shifting, and even goblins can't move on the fighter's turn. If a fighter is surrounded by 9 enemies and each enemy moves away, then yes, the fighter gets 9 OAs, one per opponent.
Hello, I have a question that I didn't see posted in this thread or another about Fighter Features : can a single attack from a monster trigger both Combat Challenge *and* an OA (enhanced with Combat Superiority) ?
For example, a marked monster adjacent to my fighter foolishly makes a ranged attack against one of my allies. The attack does not include me, so Combat Challenge is triggered, and the attack is ranged, so an OA is triggered. Am I allowed to make 2 melee basic attacks in succession (assuming I didn't use any interrupt actions this round), one for the CC feature and one OA ?
Also, I'm not sure if it matters much, but which one would be resolved first ?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.