Here is the full list of all 61 Fallen Legion achievements.
Perform a link attack.
Deflect an enemy attack with a perfect block.
Complete One Life mode
Unlock Sins of an Empire's epilogue.
Unlock Flames of Rebellion's epilogue.
Complete a 50-chain.
Complete a 100-chain.
Find a celestial gem.
Trigger break mode while fighting the Volcanic Dragon.
Trigger break mode while fighting G'ndarak.
Trigger break mode while fighting the Khalecdon Hydra.
Trigger break mode while fighting Menrva.
Trigger break mode while fighting the Wraith.
Trigger break mode while fighting the Grimoire's final form.
Earn a S-rank in a stage.
Survive a battle with only Princess Cecille standing.
Unlock Chaos Zulfiqar.
Unlock Order Zulfiqar.
Unlock Chaos Longinus.
Unlock Order Longinus.
Unlock Chaos Apollon.
Unlock Order Apollon
Unlock Chaos Winchester.
Unlock Order Winchester.
Unlock Chaos Mjolnir.
Unlock Order Mjolnir.
Unlock Chaos Dardanelles.
Unlock Order Dardanelles.
Master many deathblows.
Use two of the same Exemplar in battle.
Use three of the same Exemplar in battle.
Defeat the Emissaries of the Hound.
Discover the truth in the Sylene Academy.
Explore the Vergone Ruins.
Prevent the Charred Pox from spreading.
Visit the Pantheon of the Distant Sea.
Choose Prime Legion cards 25 times.
Choose Council of Princes cards 25 times.
Choose March Congress cards 25 times.
Use the Wildfire spell.
Use the Cassandra's Lunacy spell.
Use the White Staccato spell.
Use the Psyche Devourer spell.
Trigger break mode while fighting the Manticore
Trigger break mode while fighting the Vandee Werewolf.
Trigger break mode while fighting Micena.
Trigger break mode while fighting the Crystal Golem.
Trigger break mode while fighting General Aurelius.
Trigger break mode while fighting the Throne's final form.
Inflict over 9,000 damage without breaking the chain meter.
Rescue Princess Agnes in her time of need.
Discover the secret in Styricaem.
Join a raid with Constantine.
Face the Order of the Bleeding Axe.
Defeat the Ouroboros Cypress.
Complete the first act in Flames of Rebellion.
Complete the second act in Flames of Rebellion.
Complete the third act in Flames of Rebellion.
Complete the first act in Sins of an Empire
Complete the second act in Sins of an Empire
Complete the third act in Sins of an Empire.