Here is the full list of all 35 Monochrome Order achievements.
Fame has risen to 30 or higher.
Peace has risen to 30 or higher.
Economy has risen to 30 or higher.
Won 50 battles.
Gained 5 party members.
Completed 10 Judgments.
Won 10 battles.
Completed 3 Judgments.
Gained 3 party members.
Tempered a weapon to Lv. 15.
Tempered a weapon to Lv. 35.
Tempered a weapon to Lv. 50.
Gained 1,000G.
Completed 20 Judgments.
Completed 30 Judgments.
Won 100 battles.
Won 250 battles.
Gained 7 party members.
Gained 10 party members.
Fame has fallen to -30 or lower.
Peace has fallen to -30 or lower.
Economy has fallen to -30 or lower.
Gained 100,000G.
Gained 200,000G.
Defeated Calamititan.
Defeated the Betrayer.
Defeated Anarchaos.
Defeated Despair Dragon.
Defeated all boss enemies.
Cleared the ending "A New Order."
Cleared the ending "Divine Enemy Protector."
Cleared the ending "An Organization in Pieces."
Cleared the ending "Inevitable Destruction."
Cleared the ending "Dragon's Pardon."
Cleared all endings.