Just thought I'd add this in, The quad att on this weapon acts like a job trait. and when off handing this weapon, I have had my main hand weapon quad attack.
The drain effect is ~100%, and so far in the 12 hours I've had it (using it only 2x), I've seen it drain up to 9 tp/hit. That's like...an extra attack round.
This dagger would be an offhand dagger. For THF your main hand dagger should be your highest DMG dagger for WS, right now there are lots of better options like Empyrian, relic, kila etc.
The offhand dagger should be your low delay or otherwise TP building dagger. That's where this comes in, with the extra Quadruple attack and occaisional TP drain, this dagger looks like it will get you to your WS faster than blau, rapidus, auric or other offhand daggers.
Obtained from Shinryu, Blue procs greatly increases drop rate on Shin from "This thing doesn't drop anything" to "Meh, I guess it could drop something if you're lucky." Very good dagger for off handing. Should always main hand highest DMG dagger.
Was farming up lights in Abyssea-Vunk on bats and found that the drain effect only took effect bout 35% of the time leading me to believe that even the weapons drain effect are dark based like the various spells. Doubt this is new info but yeah ^^