To get answers of the said blade is rather difficult as divinations fail vs artifacts by default and no commune nor divinations would not give answers. So you need ask some other sources than spells for it. Also cool reward was meant to be blade itself; once you get artifact mastered it has some cool perks. Or find some fool mortal wield it and cause chaos on your enemies or in prime material plane. As blade is something more than just 'inteligent unholy avenger'.