"Vital Critbowsman" Fighter, Lore Warden; Human (FUCKING RIDICULOUS)

Self-Interested Preface: This character was created as a dual exercise both to see how high damage can be boosted and to get some ranged use out of the amazing Destroy Identity feat, a critical feat that damages CHA by 2 and staggers opponents for one round with NO SAVE.  Adding a familiar, however, necessitates worship of Calistria, a non-evil god, which precludes Destroy Identity from this specific build.  After doing some research and rebuilding this character twice, its current and final iteration has traded out its critical hit focus for a much more reliable Vital Strike build, combined with the Overwatch Style chain to do what I'm pretty sure is the most consistent highest damage per round I've ever seen in a build.  At level 20, this character maxes out at between 212-660 damage per round with an enchanted +5 large heavy crossbow, assuming no critical hits and a full-round four-readied-attacks action.  That's a shitty example, though, since no one'll ever play to level 20, so for a more detailed breakdown by level, scroll down to below this build to see this character's base attack and damage with modifiers, assuming no enhancements or items aside from a large heavy crossbow and, when relevant, a Gravity Bow spell effect.  Through use of a too-large weapon (taking a -2 for oversized wielding), Weapon Training, Point-Blank Shot, the Focused Weapon Advanced Weapon Training, the Vital Strike feat chain, Weapon Specializations, and Gravity Bow, each damage roll will use so many fucking die you'll get kicked out of the campaign for knocking over some part of the combat area every round multiple times every combat.  I mean, you could just use a die-rolling app but let's be honest for a second, that's bitch as fuck.

This character's pretty feat-intensive, owed mainly to using crossbows which are very feat-intensive weapons.  I went crossbow because the critical range is greater and the base damage is higher than bows.  As such, Human is pretty much the only way to go- if this were to be a longbow build, however, I'd go Strix for the racial flight ability, bonus to DEX, built-in darkvision and dump stat penalty.  There'd also be room for adding the Called Shot feats, adding a good amount of versatility to the regular damage-dealing this character does(with Improved Called Shot, called shots can be made as part of the Overwatch Style actions).  Might do that some other time, I guess.  There's actually an archetype for fighters using crossbows and readied attacks called Crossbowman, which was the original archetype for this build.  There are only two abilities of real note in the archetype, however- one is a free Point Blank Master equivalent, and the other allows a retaliatory shot as an immediate action when struck by a ranged attack.  The other abilities add DEX to damage for readied shots and boost sniping, which, while not completely terrible, are still much worse than the Advanced Weapon Training fighter abilities they replace(added recently by the Weapon Master's Handbook).  As such, I went Lore Warden, since this character's meant to use light armor anyway and has fantastic use for the Lore Warden's swift-action (after level 14) +2 attack/damage bonus as well as the extra skills and immediate-action Acrobatics-roll critical negation.  The massive CMB/CMD boost isn't terrible, either.

Wasp Familiar, gained at level 9, allows for much greater action economy as your familiar uses wands in-combat for spell buffs like Gravity Bow and Coward's Cowl to boost ranged damage and attacks/AC/saves, respectively.  It's the Figment archetype, which means it gains evolutions which it uses to greatly boost its Use Magic Device skill as well as improve its versatility for whatever else you'd like it to do and keep it from ever dying permanently(dead Figment familiars always return each morning).  Finally, it adds the greensting scorpion's +4 Initiative bonus and a free Alertness feat when adjacent (which should be always).  I didn't put up the statblock for every level of the wasp familiar because that sounded really fuckin tiresome for something that only exists to use wands.  Maybe someday?  Probably not.

I could probably gush about this build a little more, but the by-level breakdown of attack and damage pre-item shows this character's capability better than my self-important nerd-ass prose.  Scroll down to the bottom and look- it's fucking ridiculous the kind of damage this character puts out when Overwatch Vortex and the various Vital Strikes come into play.  The final thing I'd like to mention is the Massive Damage optional rule, which states that if half a susceptible creature's hitpoints in damage (minimum 50) are taken from a single attack (very possible with this build) it has to make a Fortitude save or immediately die.  This character would be forcing a lot of that.

Build created in November of 2015, then overhauled a few times before being finalized in May of 2016.

Fighter (Lore Warden), Level 20

Race: Human, +2 DEX  (+1 Hit Point/+1 Skill Point/+1 to CMD against two chosen maneuvers)

Racial Traits

Bonus Feat

Dimdweller (+2 Intimidate, Perception, and Stealth when concealed by areas of dim or lower light)

Darkvision 60'

Character Traits/Drawbacks

Drawback: (Detriment, Circumstance)

Combat: Armor Expert (armor class penalty for wearing any armor reduced by 1)

Race (Human): Latent Psion (+2 to saves against mind-affecting effects)

Religion: Well-Prepared (+1 to attacks made as a readied action)

Point Buy 20              Racial              Lvl. 4               Lvl. 8               Lvl. 12             Lvl. 16             Lvl. 20

STR     11                   

DEX    17                    19                    20                    21                    22                    23                    24

CON   14                   

INT     10                   

WIS     14

CHA   7                     

Class Skills: Acrobatics, Bluff, Climb, Craft (Any), Handle Animal, Heal, Intimidate, Knowledge (Any), Knowledge (Local), Perception, Profession (Any), Ride, Sense Motive, Sleight Of Hand, Survival, Stealth, Swim, and Use Magic Device.

Known Languages: Common

Starting Gear (175 GP): Studded Leather Armor (25 GP), Heavy Crossbow (50 GP), 50 bolts (5 GP), Spiked Gauntlet (5 GP), Caltrops x5 (5 GP),

1: Fighter (Lore Warden) 1, +1 Hit Point

            BAB: +1

            Base Saves: +4/+4/+2 (+2 to saves against mind-affecting effects)

New Feats: Simple and Martial Weapon Proficiencies, Light Armor Proficiency, [Human Feat] Point-Blank Shot, [Fighter 1^st] Rapid Shot, [1^st Level Feat] Rapid Reload (Heavy Crossbow), [Anti-Hero] Crossbow Mastery (Heavy Crossbow)

Skills(4): Knowledge (as desired), Knowledge (Local), Perception, Use Magic Device

2: Fighter (Lore Warden) 2, +1 Hit Point

            BAB: +2

            Base Saves: +5/+4/+2 (+2 to saves against mind-affecting effects, +1 against fear effects)

New Feats: Combat Expertise, [Fighter 2^nd] Precise Shot

Skills(4): Knowledge (as desired), Knowledge (Local), Perception, Use Magic Device

3: Fighter (Lore Warden) 3, +1 Hit Point

            BAB: +3

            Base Saves: +5/+5/+3 (+2 to saves against mind-affecting effects)

New Feats: Maneuver Mastery +2, [3^rd Level Feat] Weapon Focus (Heavy Crossbow)

Skills(4): Knowledge (as desired), Knowledge (Local), Perception, Use Magic Device

4: Fighter (Lore Warden) 4, +1 Hit Point

            BAB: +4

            Increased Ability Score: DEX +1 (20)

            Base Saves: +6/+6/+3 (+2 to saves against mind-affecting effects)

New Feats: [Fighter 4^th] Weapon Specialization (Heavy Crossbow)

Skills(4): Knowledge (as desired), Knowledge (Local), Perception, Use Magic Device

5: Fighter (Lore Warden) 5, +1 Hit Point

            BAB: +5

            Base Saves: +6/+6/+3 (+2 to saves against mind-affecting effects)

New Feats: Weapon Training(+1): Crossbows, [5^th Level Feat] Overwatch Style

Skills(4): Knowledge (as desired), Knowledge (Local), Perception, Use Magic Device

6: Fighter (Lore Warden) 6, +1 Hit Point

            BAB: +6/+1

            Base Saves: +7/+7/+4

New Feats: Bravery +1, [Fighter 6^th] Vital Strike

Skills(4): Knowledge (as desired), Knowledge (Local), Perception, Use Magic Device

7: Fighter (Lore Warden) 7, +1 Hit Point

            BAB: +7/+2

            Base Saves: +7/+7/+4 (+2 to saves against mind-affecting effects)

New Feats: Maneuver Mastery +4, [7^th Level Feat] Overwatch Tactician

Skills(4): Knowledge (as desired), Knowledge (Local), Perception, Use Magic Device

8: Fighter (Lore Warden) 8, +1 Hit Point

            BAB: +8/+3

Increased Ability Score: DEX +1 (21)

            Base Saves: +8/+7/+4 (+2 to saves against mind-affecting effects)

New Feats: [Fighter 8^th] Point Blank Master (Heavy Crossbow)

Skills(4): Knowledge (as desired), Knowledge (Local), Perception, Use Magic Device

9: Fighter (Lore Warden) 9, +1 Hit Point

            BAB: +9/+4

            Base Saves: +8/+8/+5 (+2 to saves against mind-affecting effects)

New Feats: Advanced Weapon Training (+2): Versatile Training [Crossbows (Perception, Stealth)], [9^th Level Feat] Wasp Familiar, (Familiar) Alertness

Skills(4): Acrobatics x9, Knowledge (as desired), Knowledge (Local), Use Magic Device

Familiar: Wasp (as flying Greenstring Scorpion), Figment Archetype

9: Wasp; Figment archetype

HD: 9

HP: 1/4 master's HP

BAB: +9

Ability Scores: STR 3; DEX 16; CON 10; INT 10; WIS 10; CHA 2

Attack(s): Sting +12 (1d2-4) with DC 10 injury poison: sickened (duration 1/round for 6 rounds)

Size: Tiny (0 ft. reach)

Speed: 10’ Land, 40' Fly (average)

Base Saves: +6/+9/+3

Base AC: 23 (10 + 8 natural + 3 DEX + 2 size)

Current Feats and Abilities: Weapon Finesse, Alertness, Extra Item Slot: Hands, Empathic Link, Recurring Dream, Speak With Master, Manifest Dreams 2

Skills: Fly 10, Perception 9, Stealth 15, Use Magic Device 13

Evolutions(2): (1)Skilled: Use Magic Device, (as desired regarding campaign/current situation, altered each morning)

10: Fighter (Lore Warden) 10, +1 Hit Point

            BAB: +10/+5

            Base Saves: +9/+8/+5 (+2 to saves against mind-affecting effects)

New Feats: (Alertness bonus to Perception increases to +4), Bravery +2, [Fighter 10^th] Snap Shot

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), Use Magic Device

11: Fighter (Lore Warden) 11, +1 Hit Point

            BAB: +11/+6/+1

            Base Saves: +9/+8/+5 (+2 to saves against mind-affecting effects)

New Feats: Hair’s Breadth, Maneuver Mastery +6, [11^th Level Feat] Overwatch Vortex

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), Use Magic Device

12: Fighter (Lore Warden) 12, +1 Hit Point

            BAB: +12/+7/+2

Increased Ability Score: DEX +1 (22)

            Base Saves: +10/+10/+6 (+2 to saves against mind-affecting effects)

New Feats: [Fighter 12^th] Improved Vital Strike

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), Use Magic Device

13: Fighter (Lore Warden) 13, +1 Hit Point

            BAB: +13/+8/+3

            Base Saves: +10/+10/+6 (+2 to saves against mind-affecting effects)

New Feats: Advanced Weapon Training(+3): Focused Weapon (Heavy Crossbow), [13^th Level Feat] Improved Snap Shot

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), Use Magic Device

14: Fighter (Lore Warden) 14, +1 Hit Point

            BAB: +14/+9/+4

            Base Saves: +12/+10/+6 (+2 to saves against mind-affecting effects)

New Feats: Bravery +3, Swift Lore, [Fighter 14^th] Combat Reflexes

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), Use Magic Device

15: Fighter (Lore Warden) 15, +1 Hit Point

            BAB: +15/+10/+5

            Base Saves: +12/+11/+9 (+2 to saves against mind-affecting effects)

New Feats: Maneuver Mastery +8, [15^th Level Feat] Iron Will

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), Use Magic Device

16: Fighter (Lore Warden) 16, +1 Hit Point

            BAB: +16/+11/+6/+1

Increased Ability Score: DEX +1 (23)

            Base Saves: +13/+11/+9 (+2 to saves against mind-affecting effects)

New Feats: [Fighter 16^th] Greater Vital Strike

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), +1 other

17: Fighter (Lore Warden) 17, +1 Hit Point

            BAB: +17/+12/+7/+2

            Base Saves: +13/+11/+12 (+2 to saves against mind-affecting effects)

New Feats: Advanced Weapon Training(+4): Armed Bravery, [17^th Level Feat] Devastating Strike

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), +1 other

18: Fighter (Lore Warden) 18, +1 Hit Point

            BAB: +18/+13/+8/+3

            Base Saves: +14/+12/+15 (+2 to saves against mind-affecting effects)

New Feats: Bravery +4, [Fighter 18^th] Greater Weapon Focus (Crossbow)

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), +1 other

19: Fighter (Lore Warden) 19, +1 Hit Point

            BAB: +19/+14/+9/+4

            Base Saves: +14/+12/+15 (+2 to saves against mind-affecting effects)

New Feats: Know Weakness, [19^th Level Feat] Greater Weapon Specialization (Heavy Crossbow)

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), +1 other

20: Fighter (Lore Warden) 20, +1 Hit Point

            BAB: +20/+15/+10/+5

Increased Ability Score: DEX +1 (24)

            Base Saves: +15/+13/+15 (+2 to saves against mind-affecting effects)

New Feats: Weapon Mastery (Heavy Crossbow), [Fighter 20^th] Critical Versatility

Skills(4): Acrobatics, Knowledge (as desired), Knowledge (Local), +1 other

Level 1 Attack: BAB (+1) + DEX (+4) + readied action (+1) + Large Heavy Crossbow (-2) = +4

(+5 with Point-Blank Shot; cannot use Rapid Shot full-attack action as reload is still a move action)

Level 1 Damage Per Shot: Large Heavy Crossbow (2d8)

            (+1 with Point-Blank Shot)

Level 2 Attack: BAB (+2) + DEX (+4) + readied action (+1) + Large Heavy Crossbow (-2) = +5

(+6 with Point-Blank Shot, +2/+2 as full-attack with Rapid Shot, +3/+3 with Point-Blank Rapid 

Shot)

Level 2 Damage Per Shot: Large Heavy Crossbow (2d8)

            (+1 with Point-Blank Shot)

Level 3 Attack: BAB (+3) + DEX (+4) + readied action (+1) + Weapon Focus (+1) + Large Heavy 

            Crossbow (- 2) = +7

(+8 with Point-Blank Shot, +4/+4 as full-attack with Rapid Shot, +5/+5 with Point-Blank Rapid 

Shot)

Level 3 Damage Per Shot: Large Heavy Crossbow (2d8)

            (+1 with Point-Blank Shot)

Level 4 Attack: BAB (+4) + DEX (+5) + readied action (+1) + Weapon Focus (+1) + Large Heavy 

            Crossbow (- 2) = +9

(+10 with Point-Blank Shot, +6/+6 as full-attack with Rapid Shot, +7/+7 with Point-Blank Rapid 

Shot)

Level 4 Damage Per Shot: Large Heavy Crossbow (2d8) + Weapon Specialization (+2)

            (+1 with Point-Blank Shot)

Level 5 Attack: BAB (+5) + DEX (+5) + readied action (+1) + Weapon Focus (+1) + Weapon Training  

             lvl. 5 (+1) + Large Heavy Crossbow (-2) = +11

(+12 with Point-Blank Shot, +9/+9 as full-action Overwatch Style attack, +10/+10 as full-action  

Overwatch Style attack with Point-Blank Shot)

Level 5 Damage Per Shot: Large Heavy Crossbow (2d8) + Weapon Specialization (+2) + Weapon 

            Training  lvl. 5 (+1)

            (+1 with Point-Blank Shot)

Level 6 Attack: BAB (+6) + DEX (+5) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl. 5 (+1) + Large Heavy Crossbow (-2) = +12

(+13 with Point-Blank Shot, +10/+10 as full-action Overwatch Style attack, +11/+11 as full-action             Overwatch Style attack with Point-Blank Shot)

Level 6 Damage Per Shot: Large Heavy Crossbow Vital Strike (2d8x2) + Weapon Specialization (+2) +  

            Weapon Training lvl. 5 (+1)

            (+1 with Point-Blank Shot)

Level 7 Attack: BAB (+7) + DEX (+5) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl. 5 (+1) + Large Heavy Crossbow (-2) = +13

(+11/+11 as standard-action Overwatch Tactician attack, +12/+12 as standard-action Overwatch  

Tactician attack with Point-Blank Shot)

Level 7 Damage Per Shot: Large Heavy Crossbow Vital Strike (2d8x2) + Weapon Specialization (+2) +  

            Weapon Training lvl. 5 (+1)

            (+1 with Point-Blank Shot)

 

Level 8 Attack: BAB (+8) + DEX (+5) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl.5 (+1) + Large Heavy Crossbow (-2) = +14

(+12/+12 as standard-action Overwatch Tactician attack, +13/+13 as standard-action Overwatch  

Tactician attack with Point-Blank Shot)

Level 8 Damage Per Shot: Large Heavy Crossbow Vital Strike (2d8x2) + Weapon Specialization (+2) +  

            Weapon Training lvl. 5 (+1)

            (+1 with Point-Blank Shot)

Level 9 Attack: BAB (+9) + DEX (+5) + readied action (+1) + Weapon Focus (+1) + Weapon Training  

             lvl. 9 (+2) + Large Heavy Crossbow (-2) = +16

(+14/+14 as standard-action Overwatch Tactician attack, +15/+15 as standard-action Overwatch  

Tactician attack with Point-Blank Shot)

Level 9 Damage Per Shot: Large Heavy Crossbow Vital Strike (2d8x2) + Weapon Specialization (+2) +   

            Weapon Training lvl. 9 (+2)

            (+1 with Point-Blank Shot) (3d8 base damage with Gravity Bow)

Level 10 Attack: BAB (+10) + DEX (+5) + readied action (+1) + Weapon Focus (+1) + Weapon 

             Training lvl. 9 (+2) + Large Heavy Crossbow (-2) = +17

(+15/+15 as standard-action Overwatch Tactician attack, +16/+16 as standard-action Overwatch  

Tactician attack with Point-Blank Shot)

Level 10 Damage Per Shot: Large Heavy Crossbow Vital Strike (2d8x2) + Weapon Specialization (+2) +             Weapon Training lvl. 9 (+2)

            (+1 with Point-Blank Shot) (3d8 base damage with Gravity Bow)

Level 11 Attack: BAB (+11) + DEX (+5) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl. 9 (+2) + Large Heavy Crossbow (-2) = +18

(+16/+16 as standard-action Overwatch Tactician attack, +16/+16/+16/+16 as full-action 

Overwatch Vortex attack) (+1 with Point-Blank Shot)

Level 11 Damage Per Shot: Large Heavy Crossbow Vital Strike (2d8x2) + Weapon Specialization (+2) +             Weapon Training lvl. 9 (+2)

            (+1 with Point-Blank Shot) (3d8 base damage with Gravity Bow)

Level 12 Attack: BAB (+12) + DEX (+6) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl. 9 (+2) + Large Heavy Crossbow (-2) = +20

(+18/+18 as standard-action Overwatch Tactician attack, +18/+18/+18/+18 as full-action 

Overwatch Vortex attack) (+1 with Point-Blank Shot)

Level 12 Damage Per Shot: Large Heavy Crossbow Improved Vital Strike (2d8x3) + Weapon 

            Specialization (+2) + Weapon Training lvl. 9 (+2)

            (+1 with Point-Blank Shot) (3d8 base damage with Gravity Bow)

Level 13 Attack: BAB (+13) + DEX (+6) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl.13 (+3) + Large Heavy Crossbow (-2) = +22

(+20/+20 as standard-action Overwatch Tactician attack, +20/+20/+20/+20 as full-action 

Overwatch Vortex attack) (+1 with Point-Blank Shot)

Level 13 Damage Per Shot: Large Heavy Crossbow Focused Weapon Improved Vital Strike (2d8x3) + 

            Weapon Specialization (+2) + Weapon Training lvl. 13 (+3)

            (+1 with Point-Blank Shot) (3d8 base damage with Gravity Bow)

 

Level 14 Attack: BAB (+14) + DEX (+6) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl.13 (+3) + Large Heavy Crossbow (-2) = +23

(+21/+21 as standard-action Overwatch Tactician attack, +21/+21/+21/+21 as full-action 

Overwatch Vortex attack) (+1 with Point-Blank Shot)

Level 14 Damage Per Shot: Large Heavy Crossbow Focused Weapon Improved Vital Strike (2d8x3) + 

            Weapon Specialization (+2) + Weapon Training lvl. 13 (+3)

            (+1 with Point-Blank Shot) (3d8 base damage with Gravity Bow)

Level 15 Attack: BAB (+15) + DEX (+6) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl. 3 (+3) + Large Heavy Crossbow (-2) = +24

(+22/+22 as standard-action Overwatch Tactician attack, +22/+22/+22/+22 as full-action 

Overwatch Vortex attack) (+1 with Point-Blank Shot)

Level 15 Damage Per Shot: Large Heavy Crossbow Focused Weapon Improved Vital Strike (3d6x3) + 

            Weapon Specialization (+2) + Weapon Training lvl. 13 (+3)

            (+1 with Point-Blank Shot) (4d6 base damage with Gravity Bow)

Level 16 Attack: BAB (+16) + DEX (+6) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl. 13 (+3) + Large Heavy Crossbow (-2) = +25

(+23/+23 as standard-action Overwatch Tactician attack, +23/+23/+23/+23 as full-action 

Overwatch Vortex attack) (+1 with Point-Blank Shot)

Level 16 Damage Per Shot: Large Heavy Crossbow Focused Weapon Greater Vital Strike (3d6x4) + 

             Weapon Specialization (+2) + Weapon Training lvl. 13 (+3)

            (+1 with Point-Blank Shot) (4d6 base damage with Gravity Bow)

Level 17 Attack: BAB (+17) + DEX (+6) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl. 17 (+4) + Large Heavy Crossbow (-2) = +27

(+25/+25 as standard-action Overwatch Tactician attack, +25/+25/+25/+25 as full-action 

Overwatch Vortex attack) (+1 with Point-Blank Shot)

Level 17 Damage Per Shot: Large Heavy Crossbow Focused Weapon Greater Vital Strike (3d6+6x4) + 

             Weapon Specialization (+2) + Weapon Training lvl. 17 (+4)

            (+1 with Point-Blank Shot) (4d6 base damage with Gravity Bow)

Level 18 Attack: BAB (+18) + DEX (+6) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl. 17 (+4) + Greater Weapon Focus (+1) + Large Heavy Crossbow (-2) = +29

(+27/+27 as standard-action Overwatch Tactician attack, +27/+27/+27/+27 as full-action 

Overwatch Vortex attack) (+1 with Point-Blank Shot)

Level 18 Damage Per Shot: Large Heavy Crossbow Focused Weapon Greater Vital Strike (3d6+6x4) +  

            Weapon Specialization (+2) + Weapon Training lvl. 17 (+4)

            (+1 with Point-Blank Shot) (4d6 base damage with Gravity Bow)

Level 19 Attack: BAB (+19) + DEX (+6) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl. 17 (+4) + Greater Weapon Focus (+1) + Large Heavy Crossbow (-2) = +30

(+28/+28 as standard-action Overwatch Tactician attack, +28/+28/+28/+28 as full-action 

Overwatch Vortex attack) (+1 with Point-Blank Shot)

Level 19 Damage Per Shot: Large Heavy Crossbow Focused Weapon Greater Vital Strike (3d6+6x4) + 

            Weapon Specialization (+2) + Weapon Training lvl. 17 (+4) + Greater Weapon Specialization (+2)

            (+1 with Point-Blank Shot) (4d6 base damage with Gravity Bow)

Level 20 Attack: BAB (+20) + DEX (+7) + readied action (+1) + Weapon Focus (+1) + Weapon Training 

             lvl. 17 (+4) + Greater Weapon Focus (+1) + Large Heavy Crossbow (-2) = +32

(+30/+30 as standard-action Overwatch Tactician attack, +30/+30/+30/+30 as full-action 

Overwatch Vortex attack) (+1 with Point-Blank Shot)

Level 20 Damage Per Shot: Large Heavy Crossbow Focused Weapon Greater Vital Strike (3d8+6x4) + 

            Weapon Specialization (+2) + Weapon Training lvl. 17 (+4) + Greater Weapon Specialization (+2)

            (+1 with Point-Blank Shot) (4d8 base damage with Gravity Bow)

Bracers Of Falcon’s Aim (4000 GP)

Wand of Gravity Bow (750 GP)

Large Heavy Underwater Crossbow (100 GP), Masterwork (750 GP), Greenwood (400 GP), +5 (50000 GP)

Bolts (1 SP each), Adamantine (+60 GP each)

At level 20, with the above enchanted large crossbow, adamantine bolts, and the Gravity Bow spell effect, a readied crossbow shot would deal 16d8+37 = 53-165 per shot, or between 212-660 damage per round (+1 if within 30'), with a 19-20 x4* auto-confirm crit range that can trip or bull rush and has one additional effect determined by training undertaken using Critical Versatility.

*Vital Strike damage is not multiplied on a critical hit, so the x4 multiplier would apply to the damage as rolled before Vital Strike, ending up counting as another 16d8 but adding +42 from the various damage bonuses.

The Massive Damage optional rule is as follows:

Massive Damage

If you ever sustain a single attack that deals an amount of damage equal to half your total hit points (minimum 50 points of damage) or more and it doesn't kill you outright, you must make a DC 15 Fortitude save. If this saving throw fails, you die regardless of your current hit points. If you take half your total hit points or more in damage from multiple attacks, no one of which dealt more than half your total hit points (minimum 50), the massive damage rule does not apply.