Nightmare Fuel / The Dawn of Yangchen

• Yangchen suffers a panic attack when trapped in the crawlspace under the meeting hall. The worst part might be that she's not claustrophobic—that just doesn't matter.
  She didn't know whose terror had paralyzed her, whose memories had boxed her in, but it didn’t matter. It was pure math. Out of a thousand lives, at least a few Avatars would have been debilitatingly afraid of confined spaces.
  It was their fingernails raking across the soot, seeking purchase. Their voices closing shut in a chorus of suffocation. She fought to maintain control. Avatar Yangchen isn't afraid of being buried alive. You're not going to die here. You're not going to die.
  But she had perished so many times, hadn't she? The downside of being endlessly reborn, the endless ends. Her body and mind remembered how to take a final breath.
  • Yangchen's unstable connection to her past lives in general. Well, "connection" isn't quite a good word for it. She's frequently been possessed by them.
• Yangchen refuses to let her allies know how she's incapacitating Unanimity. She calls it a "vile" technique to herself. She stands outside the room her opponent is in and she uses her Airbending to take all the air out of the room until they lose consciousness.