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