This Ichor was crafted by an old colleague of mine: Thule Ravenclaw.  He was a young, promising mage before the great war, but when the Lich King rose to power, he betrayed his brethren and allied with the Scourge.$B$BI did not realize he still lives, nor that he leads the Rot Hides in their forays against us!$B$BI know many of his spells, and can help concoct a potion to counter them.  Take this scroll back to Apothecary Renferrel.  It has the incantations needed for the potion.