Pillars of Eternity

Please check comments as people are reporting unlocking this achievement instead of the achievement for killing over 2000 and vice versa

You will want to save this achievement for your second playthrough. Understanding the games mechanics is essential.

Gamemode should be Storytime

I reached the point of no return at burial isle with 19 Kills (9 from the glitched heritage Hill level grrr), I decided to bring my party in-case the final boss was too tough, this final stretch increased my total kills to 64 so bear this in mind.. i then replayed the final level solo and finished on 28 kills. I was able to defeat the final boss at level 9 but I must stress Storytime mode is essential it would be extremely difficult to do this even on easy because of the final boss. If you are just after the achievement I advise you to take your party to the final boss it really makes things easier. if you seek glory however attempt the final battle Solo.

Quicktips
Gamemode should be Storytime mode. Travel Solo its easier to sneak. Sneak through all maps and locations, to increase speed press to activate fast mode. Save often,
Loot everything, most of your coin/equipment will come from looting. I looted £20000 by the end of defiance bay.Use Figurines to summon a distraction and use it as an opportunity to escape. Mechanics is equally as important as the stealth upgrade, keeping them about level during the early portion of the game is important. Utilise Inns for Rest Bonus, Build Dungeons, Barracks and Artificers Hall for your keep Asap. On the options screen select difficulty and check the box for show personality/reputation, this is really important and shows the consequence of each dialogue option, try to get Aggressive to 2 quickly. Ally with House Doermenal, they are rogues and thieves ALL of there quests can be completed with just 1 kill. You have to Kill Wendelto get invitation.
Heritage Hill Tower Level 1 has a bug, you are forced into combat with 1 of the group of guls, there is no way to sneak around you will stay in combat even if you get past them. i was on 10 kills until i reached this area and this brought me to 19 grrrrr. on aside note in this area send the group of prisoners from icanthas house to the top of the tower, then redirect the power into yourself for a permanent increase to might of +1. Sacrifice one of your companions at Dyrford Ruins this give a valuable +1 in a stat.

I found an excellent page devoted to a stealth run, by a player called Omnicron. it is really helpful and also lists which quests are doable without combat. https://forums.obsidian.net/topic/79761-12-kill-run-class-bu...
Use Gamepressures guide for the maps and also to see how quests can be completed quickly. https://guides.gamepressure.com/pillarsofeternity/guide.asp?... they will really help you from stumbling into enemies and ensure you get from A to B efficiently. Completing any sidequests that don't have combat is important you need all the XP you can get and a guide will help you. You can get from the start of the game to Defiance bay in just an hour with under 10 kills, aim to be level 4/5. [b
Just because enemies are blocking your path doesn't mean you cant get around them. Pay attention to your sneak icon, you can actually get pretty close they will only become alert when they icon bars has completely filled with with red.

Here is an example of how I was able to complete the Sanitariam Quest with 0 kills which should of required me to Slay dozens of Enemies.

Strategy
It is extremely important that when starting a new game you choose Storytime Mode. As you will be cutting out most quests and avoiding combat leveliing up to max level is a problem. This game mode makes combat much more favourable to the player by buffing your stats and limiting the aI'S. This is essential for completing the final boss fight.
Character Creation
Pale Elf Rogue with Drifterbonus is the best race. As combat is avoided might and constitution are useless, reduce these to both to 3 and have perception, dexterity, intelligence and resolve ALL at 18. these last 4 are extremely important for quests where combat can be avoided through dialogue. Rember for the last fight you can always retrain your character and improve your constitution and might.
talents
Crippling Strike, Escape (essential) this does not allow you to escape the battle, it allows you to reposition your self ideal when trapped between enemies , Shadowing Beyond (ESSENTIAL),THE MOST IMPORTANT ability it allows you to become invisible for 10 seconds.
Deep Pockets, gives +2 quick-slots this is essential for your figurines I had 3 figurines equipped. put the rest into defensive abilities. Making an escape makes you vulnerable and you will be hit so a high defence helps.