Overwatch is the word here.
And for that purpose, we use Overwatch-Style. Duh.
For those who don't know,
Overwatch Style,
Overwatch Tactician and
Overwatch Vortex allow you to ready multiple attacks, eventually up to four of them. This already makes the style pretty good against spellcasters. But there are ways to make the build truly good.
Ranged Weapon Trick allows two more trigger-conditions for readied attacks. They even get extra effects - one negates enemy attacks of opportunity, the other imposes a penalty of enemy saves!
Enter the
Crossbowman Fighter Archetype. Now sadly it replaces Weapon Training, but it gives us several good features in return:
- half dexterity bonus to damage with crossbows on a readied action
- denying enemies their dexterity to AC on readied attacks
Now, we get the latter ability at level 7. At this point, we also got four bonus feats out of this, which we can definitely use.
Making the best use of this demands that we get sneak attack somehow. The best choices here are Rogue and Vivisectionist Alchemist, both of which give +1D6 sneak attack per two levels.
But first, we take a level in
Bolt Ace Gunslinger. This gives us proficiency with all crossbows (including exotic ones), we no longer provoke AoOs for loading them, and we can spend grit to attack touch-AC.
Now, if it's a choice between Rogue and Vivisectionist - I'd say "Both. Both is good.".
We take five levels of
Unchained Rogue to get
- Evasion
- weapon finesse and dex-to-damage, in case we ever do any melee
- trap finding, danger sense and uncanny dodge
- two rogue talents
- one Rogues Edge/Skill Unlock
- and most importantly, debilitating injury. We can now penalize the attack rolls, armor class or movement of enemies we hit.
We then fill our remaining seven levels with
Vivsectionist Alchemist. It gives us more sneak attack, some discoveries - and some alchemy, which at this point won't be terribly strong for our level, but is definitely nice to have.
Mind you, if you want to stick with being a non-caster, you can just add on more levels of Unchained Rogue to get the same amount of sneak attack.
But there is one more trick we can pull.
Oracle Variant Multiclassing.
Specifically, grabbing the
Cold-Blooded Curse. We only really want it after 11th-level - because at that point, we get to take a move action (for half speed) whenever we hit with a readied attack. Which for us should mean "four times per turn".
Now, for that we must have the reptilian subtype. Now this can be achieved in several ways: be a
Kobold, be a
Nagaji or be a Human/Half-Elf/Half-Ork with the
Racial Heritage feat. Or, if allowed, be a
Wyvaran (they have a third-party alternate racial trait that replaces their flight-speed, if so desired).
This is purely a high-level thing though, since this whole thing is otherwise quite feat-intensive. And there are better feats you can take - this is really best if you start at high levels, or use re-training at that point
Now, how about the actual build?
Well, I won't address race. Options depend on what you want and what your GM allows, and all work - though the Wyvaran is best, followed by Human, if you want to go for Oracle-VMC eventually.
Ability Scores are easy. Dexterity, everything else is nice to have, we don't need Charisma or Strength much. Wisdom is good, we have a weak will-save.
Levels: Fighter 7/Gunslinger 1/Unchained Rogue 5/Alchemist 7, in that order
Feats:
1: Point-Blank Shot 3: Weapon Focus 5: Overwatch Style 7:
Snap Shot 9: Weapon Trick 11:
Improved Snap Shot
From here one out, you can either retrain into Oracle VMC or go for these feats: 13: Combat Reflexes 15: Critical Focus 17: Staggering Critical 19: Sneaking Precision
Fighter Bonus Feats:
1: Rapid Reload 2: Precise Shot 4: Rapid Shot 6: Overwatch Tactician
Rogue Talents:
10: Weapon Training (retrain Weapon Focus into Iron Will) 12: Combat Trick (Overwatch Vortex) 14: Ninja Trick ((Style Master (Overwatch Style) retrain Overwatch Style into Improved Critical (Crossbows) - or some earlier feat if you go for Oracle VMC)
Alchemist Discoveries:
15: Bleeding Attack 17: Infusion 19: Wings or Tumor Familiar
Oracle Revelations: (Battle Mystery):
War Sight, Resiliency, Iron Skin
Magic Items:
Sniper Googles are essential to apply your sneak attack beyond 30 feet.
We end up with a BAB of +18, a Fortitude-save of +14, a Reflex-save of +14 with Evasion and a Will-save of +7.
We end up with four attacks per turn that can apply a penalty to their saving throws against one spell. They also come with +half dexterity and +7D6+14 (+7 points of bleed) sneak attack, as well as debilitating them and either allowing us movement, or having a good chance of applying a critical feat to the enemy.
For out-of-combat, we can disarm traps, have on average ~5 skill points per level (more with right race or good intelligence) and eventually gain some alchemy and a skill unlock.
