Enter the Dragon is a quest from Chapter 3 in The Witcher 2: Assassins of Kings.
After the meeting, dragon will show up and you will have to go up the tower to defeat it.
If you saved Phillippa, you will have gotten the dagger. After the cutscene with the dragon, you will automatically use the dagger to save the dragon. You will then get to talk to her. Continue and Iorevth will greet you.
If you saved Triss instead, then you will get the choice of killing or leaving the dragon. Triss will comment on it.
Since you never found out the identity of the dragon, after the cutscene, you will get to slay it or leave it be. Triss or Roche will have minor reaction to whether you killed the dragon or not.
- Geralt ran for Síle de Tansarville as fast as his legs would carry him. He could hear the sorceress' voice in his head, and the more she said, the more he wanted to silence her. Yet Síle held one more trump card - the dragon.
- If Geralt choses to kill the dragon:
- Defeating the dragon was one of Geralt's greatest feats. It was a difficult fight, even the slightest mistake could have meant instant death. Yet an ever harder task now awaited the bruised and fatigued witcher - he had to settle things with Letho.
- If Geralt choses not to kill the dragon:
- Geralt spared the dragon's life, or perhaps I should say he spared Saskia, even though the sorceresses may have still had a hold on her mind. In any case, it all played out in agreement with the witcher's code (and it matters little if this code is a fiction or not), which forbids the slaying of sapient beasts. The dragon was not Geralt's true enemy - unlike Letho. It was him that Geralt had a score to settle.