Though Nial was not actually able to use any of the techniques he learned from the Late God of Darkness' memories, he could use altered versions of this Ten Thousand Nights use. Being a technique that was applied to his body and the armaments he wields, Nial was able to use his dark energy for the latter.
With a tremendous amount of dark energy and a shroud of crimson chaos that dulled the weapon, Nial didn't need to hold back anymore. He moved the rows of his opponents like the Grim Reaper. The only difference was that he didn't use a razor-sharp scythe but a dull sword to knock out his opponents, after disarming them.