Once you have your Wightslayer, talk to the BLU NPC in gobbie shop in lower jeuno. then you get 250 WS points to break it... took me ~1.5 hours with a sam doing kasha > savage for light.
it pwns.
Skillchains with Asuran Fists to make Liquefaction.
Skillchains with Cannonball to make Fusion.
Skillchains with Vertical Cleave to make... Darkness.
Enjoy my fellow BLUs... we have darkness again.
I suspect it has Attack/Accuracy/STR/MND mods on it, as my full denali set with accuracy belt dealt more dmg than AF body + STR gear. Also, it is the new solo melee weapon of choice, as it deals like 100-300 dmg on average more than Vorpal Blade.