Here is the full list of all 17 Abyss Odyssey achievements.
Finish the prologue.
Defeat the shopkeeper.
Defeat Paganini, the Demon Violinist.
Defeat Verbum Dei.
Defeat the Living Creature.
Defeat the Warlock.
Unlock the Pincoya.
Capture a level 10 enemy.
Capture a level 25 enemy.
Capture a level 40 enemy.
Uncover the Warlock's secret.
Equip Katrien with 3 fully upgraded special attacks.
Equip the Ghost Monk with 3 fully upgraded special attacks.
Equip the Pincoya with 3 fully upgraded special attacks.
Defeat the Warlock in nightmare difficulty, "Coop Friendly Fire" must be on.
Defeat the Golem.
Win 5 online versus matches in one session.