Apparently you can pick this quest up multiple times just by nodding at him while doing it. It doesn't seem to let you complete it multiple times, though. But yeah...an excerpt from my quests.

<51> Emerald Forest: Imbessar's Warcries
+ Repeat in a whisper, 'The orc howls loud and long'
<51> Emerald Forest: Imbessar's Warcries
+ Repeat at the top of your lungs 'Spiders crawl through the forests and lay with the demons within!'
<51> Emerald Forest: Imbessar's Warcries
+ Go to the center of the pond and yell 'The water feels good while I wash my dirty feet in it!'


It wouldn't let me move the extra past the point where my farthest piece is.

wilderness <747hp 432m 648mv 14700tnl (0.00%) 2 AM>
nod imbessar
You nod at Imbessar of the Dead Star.
Imbessar of the Dead Star sighs and says 'That is not what I asked you to say. Let us try it again, and hope that you are not as thick-skulled as you seem.'