Here is the full list of all 57 Star Wars Knights of the Old Republic II: The Sith Lords achievements.
Reduce a companion's Influence to zero.
Learn how to kill Jedi from HK-47
Reach Player Level 30
Acquire all Light Side Powers
Have 30 points in Stealth
Have 30 points in Demolitions.
Teach the Handmaiden the ways of the Force.
Listen to HK-47's definition of love.
Reach maximum Light Side points
Learn Moving Meditation
Have your character replace any of the Sith Lords on the main menu screen.
Complete the game on the Dark Side
Have 30 points in Treat Injury.
Install HK-47's unique module
Change your mind about siding with the Settlers at Khoonda
Acquire all Dark Side Powers.
Kill all the Jedi masters
Recruit the Disciple
Side with Vaklu on Onderon
Reach maximum Dark Side points
Have Persuasion over 30
Deduce G0-T0's identity
Break Hanharr's spirit
Recruit Hanharr
Learn Force Sight
Complete the Handmaiden Battle Circle
Destroy Peragus Astroids
Kill all Sith troopers before they can board the Ebon Hawk
Win a Pazaak game with a full board
Complete the game on the Light Side
Defeat Sion
Claim Darth Nihilus' mask.
Defeat Nihilus
Side with the Settlers at Khoonda
Get the named Lightsaber crystal
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
Gain a Prestige class
Complete the Mandalorian Battle Circle
Collect 10,000 credits
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.
Recruit Mira
Contruct your first Lightsaber
Have 30 points in Repair.
Have 30 points in Computer Use.
Recruit the Handmaiden
Let the Sith destroy the Peragus Asteroids
Dance for Vogga
Complete the Prologue
Get your first Light Side points
Get your first Dark Side points