Buildup of the tension during the whole pursuit starting in the mid of Yavin Praxeum raid. Getting through all the puzzles and tricks underneath the Praxeum, the atmosphere of Praxeum's underground, that overall feel of something ancient and mystical about it with all those weird traps and illusions. Their dialogue before the fight, kept pretty normal and natural.
The fact that with Desann being actually a really poor, simple character, there was some sort of acknowledgement he is not anybody special or epic. Bad guy, head of the sick fuggots, but besides being incredibly dangerous, he was no big deal in terms of character. He was just bad, he needed to die, nothing more to it. I liked that they didn't give the actual dialogue between them and the fight itself some unnecessary heroics and emotional drama behind it. Desann was a simple guy, Kyle had to kill him to get rid of all the sh*t. Their dialogue represented that; Kyle remained his sarcastic self, they both acknowledged each other's "importance" as obstacles and their respective power, but there was no emotional nonsense.
Then - Desann's death being just a corpse over there after the fight, and Kyle just jumping outside without any unnecessary dramatic scenes. The guy is finally dead, Kyle processes the thought and finally just walks out of the scene, because there's not much left you can do after being out of stamina after all that jazz and being finally free of Desann. Like, it's normal, when you're finally done with your biggest grief, you just walk out with a sigh, having a relief and wanting to lay down on a couch and watch some movies. That's what I liked about Desann's death and game's ending - no dramatic scenes, no heroics, no deep monologues, no poetry. Kyle finally killed the fuggot, can walk out of it, peaceful music starts to play.