Here is the full list of all 57 Star Wars Knights of the Old Republic II: The Sith Lords achievements.
Break Hanharr's spirit
Teach the Handmaiden the ways of the Force.
Recruit Hanharr
Reduce a companion's Influence to zero.
Reach maximum Dark Side points
Recruit the Handmaiden
Complete the Handmaiden Battle Circle
Win a Pazaak game with a full board
Destroy Peragus Astroids
Kill all Sith troopers before they can board the Ebon Hawk
Complete the game on the Light Side
Defeat Sion
Reach Player Level 30
Install HK-47's unique module
Claim Darth Nihilus' mask.
Defeat Nihilus
Have 30 points in Treat Injury.
Have 30 points in Demolitions.
Acquire all Light Side Powers
Side with the Queen on Onderon
Have 30 points in Stealth
Flee Korriban after fighting Sion
Get this by starting the "Trapped" Quest on Korriban.
Loot a body on Korriban
Have Persuasion over 30
Learn Force Sight
Fill the Party Selection screen
Complete the Mandalorian Battle Circle
Beat the champ on Nar Shadaa
Convince the "champ" to lose the game without playing.
Convince Vogga the Hutt to sell fuel to Telos.
Recruit Mira
Have 30 points in Repair.
Collect 10,000 credits
Learn Moving Meditation
Contruct your first Lightsaber
Repair the damaged droid on the Ebon Hawk
Gain a Prestige class
Side with the Settlers at Khoonda
Recruit the Disciple
Have 30 points in Computer Use.
Get the named Lightsaber crystal
Reach maximum Light Side points
Get your first Dark Side points
Let the Sith destroy the Peragus Asteroids
Dance for Vogga
Get your first Light Side points
Complete the Prologue
Complete the game on the Dark Side
Side with Vaklu on Onderon
Change your mind about siding with the Settlers at Khoonda
Acquire all Dark Side Powers.
Kill all the Jedi masters
Have your character replace any of the Sith Lords on the main menu screen.
Deduce G0-T0's identity
Learn how to kill Jedi from HK-47
Listen to HK-47's definition of love.