A disgusting Tiefling with the Large arms and prehensile tail racial features. Swamp Rat (+1 DMG with daggers) and Reactionary traits. Duel wielding size large daggers, which are exactly like short swords with a range increment.
The main idea is to pump up the BAB and get Improved Two Weapon Fighting from Slayer. The Vanguard teamwork stuff will help with his or her bodyguards.
QuickDraw and Strong Thrower and Point Blank Shot for feats during Slayer, and Snapshot Rogue Talent.
Now, the Alchemist... Never played one, never played in a party with one. But I want the BBEG to be essentially tearing off tumors and throwing them like grenades.
Help a brother out. Please.
I don't know which feats to pick out that best compliment a disgusting tumor throwing Tiefling, or even which Alchemist archetype would be best. The traps and Sapper stuff seemed fun, but maybe Grenadier is more appropriate. I don't know much about Alchemists, just really like the concept for a boss character.