Here is the full list of all 30 Avadon: The Black Fortress achievements.
Complete Avadon: The Black Fortress on Hard difficulty or higher.
Complete Avadon: The Black Fortress on Torment difficulty.
Send Beloch the Scourge back where it came from. (Hard difficulty or higher.)
Reach Castle Vebeaux without one of your characters ever going unconscious. (Hard difficulty or higher.)
Complete Avadon: The Black Fortress on Normal difficulty or higher.
Claim Avadon for your own. (Normal difficulty or higher.)
Reach the endgame and never have more than one character beside yourself in your party. (Normal difficulty or higher.)
Reach the endgame without ever making one of your companions happy. (Normal difficulty or higher.)
Eliminate the threat to the Kva.
Reach the endgame without ever using a Resurrection scroll. (Normal difficulty or higher.)
Get your main character to level 30.
Bring all four of your allies back to Avadon.
Show that Holklandans and the Kellem can work together.
Find all codex entries.
Cleansed the Beraza Woods of bandits.
Found a secret door.
Fight your way back into the castle.
Hunted down the Shadow Beast.
Get your main character to level 20.
Augment 50 items.
Meet Redbeard.
Locate the crypt of the Keepers.
Get your main character to level 10.
Calm the dragon Zhethron. For the first time.
Prove your loyalty to Redbeard.
Purged a tower of its unspeakable experiments.
Hunt down the greatest prey. (Normal difficulty or higher.)
Showed the ogres just how foolish they were.
Augment ten items.
In the Farlands, no foe of the Pact can be left standing.