Well let's see.
Weapon wise, that's a toughie, unless you're on Premium, which as said before, Crow's Nest.
Otherwise, you have two choices before you, high damage, or high AGI, I've tried both, and I have no comments on the superiority of one over the other.
For damage, I suggest Vengeance aka Kazuro's scythe, damage is quite good, the tradeoff is it has low stats, which is mitigated by the fact it raises ALL stats and DEF by around 10+ depending on grade.
For raising AGI, the Viper's Kusari and Obsidian Kunai should do the trick, I am unsure if there are better things to dual-wield since I've found nothing else with higher AGI boosts.
For feet, any class that isn't a Priest should look into the Boots of Grief, they're in the chest right before Kazuro, stats-wise, it raises AGI and has a little bit of DEF. but the appeal of this item is that it comes with damage, the AGI just makes it even better for Assassins though it's good for Warriors as well.