Superlatively large
Would "Pirate Ninja" be a good 2 set build?.
i don't have any personal experience, but i have to say it look promising, and if i ever find a dedicated crew i'd love to use it in a melee striker type role.
think about it, pirate has some of, if not the best offenses in the game, plus the accuracy of keen aye, then ninja gives you a dodge bonus, with three more attacks, serving similar, but unique roles. you go in there, unload pirate attacks as appropriate, using mantis if you just want to shave off a little HP, or if you need stamina, dervish can knock off a mob if it gets too big for you, and hell, running six attack rings and two self-buffs at the very least will make sure you know that your purpose is to kill things, and not give you delusions of a support role, which'd just get you stuttering in your onslaught.
the one problem i could see is burning stamina waaay too fast.