Here is the full list of all 99 Mist Legacy achievements.
Become an apprentice Arcanist.
Become a wanderer of the Lunar Caravan.
Investigate your first ruin with the druids.
Become acolyte of the Circle of the Great Tree.
Defeat Hoboturla.
Activate the Prettybard portal.
Evolve Ovie.
Reach the Fort of the Mistwalkers.
Learn the basics of magic with Yolasula.
Be recognized in Kortombe.
Complete Sorka's quests.
Activate the Wellnear portal.
Be accepted at Fearpiercing Camp.
Recruit Finn Vorel.
Defeat Tortolus.
Activate the Whisper Portal.
Learn to peer into the Mists.
Recruit Corrin Fortvaillant.
Defeat Zhyxhu.
Complete the Militia Introductory Quests.
Defeat the Aquagremfyr.
Build a first barracks.
Build your first cart.
Build a first shelter.
Build an outdoor workshop.
Build a first paddock.
Help all of the scribe's friends.
Activate the Kortombe portal.
Recruit Ovie.
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 Valdiss.
Defeat Rayth.
Defeat Arriel and Ela.
Activate Corinna's portal.
Activate the Enorwen portal.
Activate Thorval Portal.
Activate the Gantras portal.
Activate the Leviathan portal.
Activate the Chimeric portal.
Activate the Norkantas portal.
Activate the Grandfall portal.
Save Ouab and become a herbalist.
Complete the quests related to the Scabonzis.
Complete the collector Innkeeper quests.
Be invited in Wellnear.
Be familiar in Larcen.
Be recognized in Gantras.
Be seefeets in Thorval.
Defeat Ilmagoth.
Defeat Bobu.
Defeat the Scabonzi guardian protector.
Defeat the Great Protector.
Defeat Gularzob.
Build a first workshop.
Build a first herbatum.
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.
Defeat Serassert.
Pass the door of justice towards Gantras.
Enter Giltanbourg.
Complete the Alchemy Learning Quests.
Integrate the guilds of Ordval for Leonidas.
Complete the Lithofortress.
Become a claw in the Assembly.
Become a Messenger of the Order of the Hippogriff.
Become squire of the Protector of the Rose.
Defeat Whuzulm.
Become Mistwalker
Defeat heroic Whulzum.
Defeat heroic Gularzub.
Defeat the Cybelfly Queen
Evolve Finn.
Defeat Hilla
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.