I thoroughly enjoy the dagger, but I'm afraid it doesn't live up to its potential. =( It could be such a greater weapon (-er because its great already). I always hear people say how much they hate it, but I love it! It really is a fun weapon. I think, with the new build coming out, they really should bring out some more high damage throwing knives and "cursed" knives.
For instance: Higher damage would be things like "Havoc Rain" (A shower of knives falling after throwing one large knife. The outcome would be an AoE massive damage hitting all enemies in the vacinity, with the possibility to stun them).
Also, something like Switch-Blade. (A throwing knife that does serious damage if struck from the back, has the chance to knock and enemy off his feet.
Blend (Come on, this should have been implemented from the start. It is basically invisibility. You're unseeable until you get within a certain line of site to an enemy. If you are behind them you are more undetectable.)
Cursed Blade (This would be the highest level skill, and will require a small amount of voodoo. It curses an enemy to take more damage from other attacks as well as stays in their bodies to do serious DoT damage. The original attack wouldn't be so strong, but the DoT would be MASSIVE)!!!
