From the latest update notes:
Atramentous Libations (Lv.99 Recast time: 180 sec.)
Steals HP from enemies within range. Ineffective against undead.
Now, I consider myself an experienced adventurer but I can't recall ever seeing this weaponskill on anything.
The wiki's aren't helping much and none of my friends in-game have a clue what monster does this skill.
My best bet is either Dullahan or Flutterini since there's so little information about them.
But if it isn't those two, then I don't know.
Can someone who has learned this spell tell me where he or she got it? Thanks in advance =)