Successfully complete one of the following tasks to get a trophy:

Commando's Seal (Bronze): Mastered the Commando role. 
Ravager's Seal (Bronze): Mastered the Ravager role. 
Sentinel's Seal (Bronze): Mastered the Sentinel role. 
Saboteur's Seal (Bronze): Mastered the Saboteur role. 
Synergist's Seal (Bronze): Mastered the Synergist role. 
Medic's Seal (Bronze): Mastered the Medic role. 
Limit Breaker (Silver): Dealt 100,000+ damage with a single attack. 
Adamant Will (Silver): Felled a heavyweight of the lowerworld wilds. 
Master's Seal (Silver): Fully developed all characters. 
Treasure Hunter (Gold): Held every weapon and accessory. 
Loremaster (Gold): Discerned the full attributes of 100 enemies.