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