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