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