Look for the sword: In moonlight streaming forth, At night, when day's first hour Reflects the North. From o'er the threshold Seek and you will see; I -- am that is, My sword shall wield for me.
The sword is slightly better damage-wise than an elven sword and can be tempered with an ingot of steel and quicksilver. On top of that, it has a script-added perk (much like the silver sword) that makes it particularly damaging to skeevers. Thanks to this, it's also fully enchantable so you can put whatever milks your Guernsey on it.
The sword can be found southeast of Sleeping Tree Camp, in a little Nordic ruin with a cage trap door that's opened by solving the pillar puzzle there. It shouldn't be too hard to find in there, just be sure to look around. This little Nordic ruin is a vanilla location, not added by me, so the mod should be right compatible with just about anything.