Many achievements are storyline based and can be easily acquired just by playing the main campaign. Harder achievements will require players to spend more time in certain areas.
You were part of a conversation wherein four players were all in agreement as to what to say.
You decided that Gunderic Manor should remain in Legion hands.
You ceded control of Gunderic Manor to Leona.
You freed all the prisoners in the Spire.
Merchant Of Ehb
You sold over 100,000 coins worth of items.
You were part of a conversation wherein four players were all in disagreement over what to say.
Of One Mind
You have agreed on dialogue choices 20 times in one session.
You have disagreed on dialogue choices 20 times in one session.
You have shown unwavering support to the Crown.
Over your career, you have sustained at least 100,000 points of damage.
Fellowship Of The Ding
You took part in a level-up while in a four-player game.
While joined to another player's game, you used an empowered Defensive Ability to assist the party.
We Are Legion
You have gathered a full party of Legion descendants.
You reached level 20 as Anjali.
Circle Of Friends
You achieved at least one level of influence with all three of your companions.
You reached level 20 as Reinhart.
You have completed the main quest as Anjali.
You reached level 20 as Lucas.
Guardian Of Ehb
You have completed the main quest as Lucas.
Lock, Stock and Invocation
You have completed the main quest as Katarina.
You achieved the highest possible influence with one of your companions.
Nerds Hate Sunlight
You and a friend have played for three hours in one session.
The Calculus of Victory
You have completed the main quest as Reinhart.
Two Perfect Tens
You reached level 20 as Katarina.
During your fight against the Dapper Old Gent, you destroyed 50 of his Automatons.
Maximum Bro Fist
Playing co-op as Lucas and Reinhart, you defeated a boss.
Moment of Solace
Force Jeyne to flee before defeating her handmaids.
You bested Rajani without needing to heal yourself.
Two Girls, One Boss
Playing co-op as Anjali and Katarina, you defeated a boss.
Aspire to Victory
You stormed the Spire and defeated Jeyne Kassynder.
You defeated the reborn god without needing to be revived by a companion.
I Could Do This Blindfolded
You defeated a major opponent using only your default equipment.
Long Live The Queen
You broke the siege of Glitterdelve and saved Queen Roslyn.
Party Of Four
You were part of a four-player party that completed the game together.
You spoke to the Radiant Youth in the Mournweald.
You've paraded about in nothing but rare items.
You forged an alliance between Stonebridge and the 10th Legion.
Through The Murky Mire
You survived a journey through the Eastern Swamp.
Trial By Fire
You defeated the archon, Rajani.
You have discovered 60 lore entries in one adventure.
View From The Top
You have achieved the maximum level.
You completed your quest, plus all other secondary quests in the game.
Welcome To The Winners Circle
You have restored the Legion and saved the land of Ehb.
Worthy Of legend
You completed Dungeon Siege III at the highest difficulty level.