Here is the full list of all 99 Mist Legacy achievements.
Defeat Ilmagoth.
Defeat Bobu.
Defeat Hilla
Evolve Finn.
Become a Messenger of the Order of the Hippogriff.
Build a first workshop.
Be familiar in Larcen.
Defeat Serassert.
Complete the Alchemy Learning Quests.
Integrate the guilds of Ordval for Leonidas.
Become an apprentice Arcanist.
Build a first herbatum.
Complete the collector Innkeeper quests.
Complete the quests related to the Scabonzis.
Activate Thorval Portal.
Become squire of the Protector of the Rose.
Defeat the Scabonzi guardian protector.
Become a claw in the Assembly.
Become a wanderer of the Lunar Caravan.
Activate Corinna's portal.
Save Ouab and become a herbalist.
Enter Giltanbourg.
Defeat Valdiss.
Defeat Hoboturla.
Pass the door of justice towards Gantras.
Defeat Rayth.
Be recognized in Kortombe.
Complete Sorka's quests.
Be accepted at Fearpiercing Camp.
Activate the Prettybard portal.
Recruit Finn Vorel.
Build your first cart.
Investigate your first ruin with the druids.
Become acolyte of the Circle of the Great Tree.
Reach the Fort of the Mistwalkers.
Activate the Enorwen portal.
Learn the basics of magic with Yolasula.
Activate the Leviathan portal.
Defeat Tortolus.
Build a first barracks.
Build a first shelter.
Build a first paddock.
Build an outdoor workshop.
Activate the Wellnear portal.
Evolve Ovie.
Activate the Whisper Portal.
Defeat Zhyxhu.
Complete the Militia Introductory Quests.
Defeat the Aquagremfyr.
Learn to peer into the Mists.
Recruit Corrin Fortvaillant.
Recruit Ovie.
Help all of the scribe's friends.
Activate the Kortombe portal.
Complete the tower construction quests.
Complete the introduction on the Troll Plateau.
Activate the Troll portal and come back to your domain.
Recruit Badouk Brank.
Recruit Palenne Roirdan.
Defeat Arriel and Ela.
Activate the Gantras portal.
Activate the Chimeric portal.
Activate the Norkantas portal.
Activate the Grandfall portal.
Be invited in Wellnear.
Be recognized in Gantras.
Be seefeets in Thorval.
Defeat the Great Protector.
Defeat Gularzob.
Build a first dispensary.
Build a first forge.
Build a first cutting plant.
Build a first sawmill.
Build a first tannery.
Build a first studio.
Complete the Lithofortress.
Defeat Whuzulm.
Become Mistwalker
Defeat heroic Whulzum.
Defeat heroic Gularzub.
Defeat the Cybelfly Queen
Defeat Hazko.
Buy the flame frame.
Build a first warehouse.
Defeat heroic Hazko.
Defeat Rylenback.
Defeat the Tarascarpel.
Defeat heroic Rylenback.
Defeat Eli'carde.
Defeat Tarathiel.
Defeat heroic Tarathiel
Defeat the army of darkness.
Defeat Cyclotus.
Complete the adventures on the island of Tinylegs
Defeat Ezhilya.
Defeat Mo'gul.
Defeat Walkrock.
Defeat heroic Ezhilya.