Here is the full list of all 17 Deadly Edge achievements.
Defeated all of the bosses in the game.
Experienced the betrayal at Rowland Keep.
Defeated Badelo.
Defeated Colossi Venichi.
Defeated the Cursed Man.
Defeated the Dark One.
Defeated Dinn of the Halberd.
Defeated Ethan the Cooper.
Defeated Gammon.
Defeated Captain Lo.
Defeated Captain Lo. Again.
Defeated the creature Loth.
Defeated Gammon's creature.
Defeated the Triplets.
Defeated the Vizier.
The oldest and strongest emotion of mankind is fear, and the oldest and strongest kind of fear is fear of the unknown.
Beat the game.