On the ground, the Wyrm is very similar to Fafnir, except that its Draw In can draw in the entire alliance if someone out of range of its normal attack pulls hate. It has the same TP attacks:
Dragon Breath: Breath Attack which can do lots of damage to anyone in front of the Wyrm. If everyone is standing on its front feet, this will only hit the main target and do relatively little damage.
Horrid Roar: Removes one random buff from the target.
Spike Flail: Only used if the target is behind the Wyrm. Extreme 30'AoE physical damage, absorbed by Utsusemi.
The Wyrm will take flight when it goes below 66% HP and will stay up until it gets down below 33% HP. While in the air, it will not use Dragon Breath, Absolute Terror, Horrid Roar or Spike Flail, but it gains the use of
While in the air, its normal attacks will look like a fireball coming from its mouth, and will do Fire damage (~325 per hit before reductions) instead of physical damage.
~220 total Fire resistance (from gear, Carol and Barspell) is enough to usually reduce its normal attack to ~12 damage, and also dramatically reduce Flame Blast damage.
Magic, Ranged Attacks, Chi Blast, and Avatars can damage it quite well while it is in the air. Melee attacks will not work.