Here is the full list of all 54 Fallen Enchantress: Legendary Heroes achievements.
Play for 100 hours.
Win as Pariden.
Win by forging an alliance with all players.
Win as Capitar.
Win as Gilden.
Win as Umber.
Win as Tarth.
Win as Yithril.
Win as Resoln.
Win as Kraxis.
Win as Magnar.
Win by having the highest score by the turn limit.
Win by completing the Master Quest.
Win by defeating all of your opponents.
Make 1000 gildar from selling items in shops.
Reach level 15 with a champion.
Create a custom sovereign.
Design a unit.
Awarded for completion of the Legendary Hero scenario.
Recruit Mausolos
Defeat a faction.
Play for 40 hours.
You defeated a sovereign in battle!
Play for 20 hours.
Win by casting the Spell of Making.
Win and have at least 3,000 population.
Win as Altar.
Get a city to level 5 in one game.
Tap 10 resources in a single game.
Not since Peter MacNicol has one been slain!
Play for 10 hours.
Control 5 cities in a single game.
Complete 10 quests in a single game.
Buy an item from a shop.
You have captured an enemy city!
Play for 5 hours.
Reach level 5 with a champion.
Explore 10 goodie huts in a single game.
Complete a quest.
Your Fame has lead a hero to your cause.
You have defeated an army!
You killed a monster!
All nations start with one.
You've managed to slay Abeix!
You've managed to slay Delin!
You've managed to slay Morian!
You've managed to slay Torax!
You've managed to slay Vetrar!
Recruit Raza the Wild
Recruit Kasst
Recruit Tuatha
Recruit Gallowman
Recruit Nen Ratcatcher
Recruit Ascian