Hi !
I did a build, and I need some advices too improve it. Magic items, better feats, good traits, better starting Stats, rogue talents, and so on. The condition is the underground chemist archetype. The eldritch scoundrel is a good addition I think, maxing Int.
This build is a middle/late game one.
Grenade launcher -
Unchained rogue - Eldritch scoundrel / Underground chemist
Kitsune -
Alternate racial trait: - Keen kitsune (+2 Dex, +2Int, -2Str) Perfect stat for this build
Superior shapeshifter: Probably better than kitsune magic here. Good for stealth
Or - skilled: If I need even more skills.
Half-elf: If you want the build to come faster, with EWP as racial trait.
20pt-
Str- 8-2
Dex- 15+2 (+1 lvl4)
Con- 12
Int- 18+2 (+4)
Wis- 10
Cha- 7
25pt-
Str- 10-2
Dex- 16+2
Con- 12
Int- 18+2 (+5)
Wis- 10
Cha- 7
I don’t max dump Str. The launching crossbow weight 8lbs. Or I take the Muscle of the society trait. With that trait, you can probably go for more Wis or Con. (A masterwork backpack can be a good idea too). But except for what I can carry, STR is useless.
For the CHA, I probably take a trait to get my Int to Diplo and/or for disguise. So, no fear to dump into oblivion charisma.
Feats:(1)Point-blank shot, (3)Rapid reload, (5)EWP(Launching crossbow), (6)Rapid shot, (7)Crossbow mastery, (9)Throw anything/Precise shot, (11)Concentrated splash
Skills-
Background: Craft(Alchemy) Reduce the cost of your bomb to ¼ is a good thing, and the underground chemist is good in alchemy. Can craft others useful thing.
Knowledge(Engineering) Can be useful, more in a world with some technologies.
Normals:Stealth, Perception, Diplomacy, Spellcraft, Acrobatic, Knowledge(Arcana/Nature/Plane/Religion) That build is good to play Know-all-Mcguy, and I need to know what is weak/immune to my elemental attack. If I take skilled, I go for Dungeoneering too.
First thing. I would not play this build if the game is low level only. I’d play magus or alchemist instead.
Lvl1-2: Play as a wizard/Alchemist: Do as much damage as the latter, and the spells of the first.
Lvl3- First Sneak attack, and Dex to damage at melee. I choose the bite attack. So, you can attack without weapon, or with something in the hands. Can go bomb or melee when needed. Still do enough damages to stay competitive with others.
Lvl4- Spells level 2. Senses vitals is a good thing here, as with Invisibility. At the end, I will have as much S.A as others rogues while active. Debilitating injuries can help to get enough touch at melee attack. The bomb are touch attack, so, no difficulty to touch enemy with it.
Lvl5- Skill Unlock: Big fan of stealth for a range build. Particularly for higher levels.
Lvl6- First talent with kitsune favored class ! Combat trick, need that feat ! With grease of obscuring mist (with a magic item), I can shot two time turn now with sneaks !
Lvl7- Big level, can use the launching crossbow without restriction. You triple the reach of your attack, and you can enchant it to get some good stuff. Also get a better S.A, and get 3rd level spell. Fly, Haste, and other good spells.
Lvl8- Rogue talent ! I think the ninja trick vanish is a good idea here. Invisibility as a swift action for a lvl1 spell is good. Get a third attack with the crossbow.
Lvl9- I prefer throw anything for that build, but Precise shot is better if you prefer use sometime a regular crossbow.
Lvl10- Rogue edge again. Stealth become good for this build, and Perception is a good addition. Lvl4 spells too. Debilitating injuring is at -6 now. Good to get some AC, or the immobilize your victim.
Lvl11- Concentrated splash add some good damages
Magic items: Weapon: Seeking and Distance are probably the funniest thing I can think for the crossbow after the +1. Can shot the flasks with a 60ft increment. And as that build is most of the time Touch attack + Flat-foot, no fear to go at 600ft and snipe that mother of a troll.
Sniper google: Needed to snipe.
Metamagic rod (Extend): After some level, with this, I can cast Sense vitals with the rod before a fight, and still have it all the fight. Can be some lesser.
Metamagic rod (Quicken): Late game. The lesser one is good, can cast half the spell list in swift.
Gloves of storing: Switch between rod and crossbow.
Ring of evasion: Good Dex, Good class’ save in reflexes. I lose it with underground chemist. The ring gives it back.
Variation - Mad bomber
As you can draw bomb easily at level 2, with Quick draw, you can attack as much as you can with your BAB and feats. That build come early, and do more damages, but on the long term, you lose greatly in reach and in touch, you can add magic property on your attacks, and it will cost way more in flask.
20pt-
Str- 7-2
Dex- 15+2 (+1 lvl8)
Con- 15 (+1 lvl4)
Int- 17+2 (+3)
Wis- 10
Cha- 7
25pt-
Str- 7-2
Dex- 15+2 (+1 lvl8)
Con- 15 (+1 lvl4)
Int- 18+2 (+3)
Wis- 10
Cha- 7
I feel like you need more health for this build, as the rogue will be more close to the enemies.
Feats: 1)Point blank shot, 3)Quick draw, 5)Rapid shot, 6)Two-weapon fighting, 7) Throw anything, 9) Concentrated splash, 11) Improved two-weapon fighting