There are 45 Trophies that can be collected.

Bronze

Guardian of Ehb
You have completed the main quest as Lucas.

Fiery Judgment
You have completed the main as Anjall.

Lock, Stock, and Invocation
You have completed the main quest as Katarina.

The Calculus of Victory
You have completed the main quest as Reinhart.

We Are Legion
You have gathered a full party of Legion descendants.

Show Off
You've paraded about in nothing but rare items.

Maximum Charisma
You achieved the highest possible influence with one of your companions.

Circle of Friends
You achieved at least one level of influence with all three of your companions.

Merchant of Ehb
You sold over 100,000 coins worth of items.

Enduring Champion
Over you career, you have sustained at least 100,000 points of damage.

Of One Mind
You have agreed on dialogue choices 20 times in one session.

Rivalry
You have disagreed on dialogue choices 20 times in one session.

Jinx
You were part of a conversation wherein four players were all in agreement as to what to say.

Military Intelligence
You were part of a conversation wherein four players were all in disagreement as to what to say.

Helping Hand
While joined to another player's game, you used an empowered defensive ability to assist the party.

Fellowship of the Ding
You took part in a level-up while in a four player game.

Nerds Hate Sunlight
You and a friend have played three hours in one session.

Archon Adept
You reached level 20 as Anjall .

Guardian Legend
You reached level 20 as Lucas.

Two Perfect Tens
You reached level 20 as Katarina.

Epic Scholarship
You reached level 20 as Reinhart.

Silver

View From the Top
You have achieved the maximum level.

Rajani's Rival
You bested Rajani without needing to heal yourself.

Archambaud's Anathema
During your fight against the Dapper Old Gent, you destroy 50 of his Automatons.

Moment of Solace
Force Jeyne to flee before defeating her handmaids.

Flawless Victory
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.

Party of Four
You were part of a four-player party that completed the game together.

Maximum Bro Fist
Playing co-op as Lucas and Reinhart, you defeated a boss.

Two Girls, One Boss
Playing co-op as Anjall and Katarina, you defeated a boss.

Loremaster
You have discovered 60 lore entries in one adventure.

Gold

Welcome to the Winner's Circle
You have restored the Legion and saved the land of Ehb.

Perfectionist
You completed your quest, plus all secondary quests in the game.

Worthy of Legend
You have completed Dungeon Siege III at the highest difficulty level.

Platinum

Dungeon Siege III Platinum Trophy
Collect all Dungeon Siege III trophies.

10 Secret

http://www.ps3trophies.org/game/dungeon-siege-iii/trophies/