As much as I love HK and as far as personality would chose him in a flash, I've gotta pick my main man, Revan.
His story is honestly one of the most compelling out of any star wars characters, which as much as I love Star Wars, has quite a few too many exclusively good or exclusively evil characters. Revan was both and came to represent the balance between the two. He was the Savior, the conqueror and then the redeemed.
Other than those two though, Kreia is still one of the best written RPG characters of all time. No party member has ever made me question each of my decisions as much as she did. Giving help to the weak? A bad thing. Being cruel to the weak? Also bad. There was no satisfying her, she was determined to make the player squirm and cross examine every choice they made.
Honestly, I could probably write an essay on why all these characters are great considering that Kotor I and II are two of my favourite games of all time (in fact, I once did) but I will just leave it at that and spare you all the blocks of text. I will simply quote the single best line about Revan:
"Savior, conqueror, hero, villain. You are all things, Revan… and yet you are nothing. In the end, you belong to neither the light nor the darkness. You will forever stand alone."
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Muwahahahahahahaha!!!What do you mean evil laugh!? This is how I always laugh!
- Bow Down: