After searching all quests in the Shadowfen area, I haven't found a quest that will reward a 1H weapon, with Sharpened and part of the Hist Sap set.
My previous comment should come closest to what you're searching for through quests.
I think your best bets for finding this kind of weapon would be:
I know i seen a list somewhere of all the unique set item quest rewards...i just dont know where i seen it
"Scissors is in a good place right now but Paper is way OP"-Rock "Rock is in a good place right now but Scissors is way OP"-Paper "Paper is in a good place right now but Rock is way OP"-Scissors