You've found an odd sliver of crystallized mana on the corpse of the tainted arcane wraith. The sliver is different than others you may have seen in that it is as dark and sinister-looking as the wraith you looted it from. Just holding it gives you a sense of unnatural foreboding.
Arcanist Helion at the gazebo of the Sunspire on Sunstrider Isle just might be someone who would have a use for the sliver.
From your demeanor, you seem to be on a matter of some urgency. Is there something specific I can assist you with?
This is... most interesting. And when I say interesting, I mean more disturbing than anything else.
Our efforts to reassert control over the isle in the time following the destruction of the Sunwell have been a challenge. I suspect that whatever foul source is corrupting the isle is at the heart of it all; this sliver may be of some aid in uncovering what's really going on.
You were wise to bring this to me, <Name>. Take this as compensation for your diligence. Thank you.