Dagger has the highest base dmg next to Perseus harpe and Mandau which means higher WS dmg. Only flaw is that the delay is dangerously close to that of a sword. So you should offhand a low delay dagger such as Sirocco Kukri.
This is a great dagger to main hand at lvl 68. Considering all daggers before lvl 68 are 10+ damage weaker than this one, this is something you'll want one way or another until you can get something better.
Drops off Citipati in Attohwa Chasm. Spawns ever 3-4 game nights. Drop rate unknown.
I don't know why Lovie is being rated down. This dagger makes a huge difference in Campaign Battles.
Let's face it THF doesn't get a lot of party invites, so there's a good chance you'll be doing a lot of Campaigning for experience points. This dagger helps in this tremendously, I can attest to this personally. My Sneak Attack + Evisceration did around 400 on Campaign mobs before this dagger and about 600-700 with it. The experience points I received at the end of battle also increased by about 30-40%. This dagger is worth getting, at the very least until Lv.72 if you can afford a Blau Dolch.
