Here is the full list of all 99 Mist Legacy achievements.
Defeat Rayth.
Complete the collector Innkeeper quests.
Defeat Valdiss.
Integrate the guilds of Ordval for Leonidas.
Become a claw in the Assembly.
Become an apprentice Arcanist.
Defeat Tortolus.
Save Ouab and become a herbalist.
Defeat Hoboturla.
Pass the door of justice towards Gantras.
Investigate your first ruin with the druids.
Become acolyte of the Circle of the Great Tree.
Activate the Prettybard portal.
Be recognized in Kortombe.
Learn the basics of magic with Yolasula.
Activate the Enorwen portal.
Be accepted at Fearpiercing Camp.
Become a wanderer of the Lunar Caravan.
Reach the Fort of the Mistwalkers.
Build a first shelter.
Complete Sorka's quests.
Recruit Finn Vorel.
Activate the Wellnear portal.
Recruit Corrin Fortvaillant.
Evolve Ovie.
Activate the Whisper Portal.
Defeat Zhyxhu.
Learn to peer into the Mists.
Build an outdoor workshop.
Complete the Militia Introductory Quests.
Defeat the Aquagremfyr.
Build your first cart.
Build a first barracks.
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 Corinna's portal.
Activate Thorval Portal.
Activate the Gantras portal.
Activate the Leviathan portal.
Activate the Chimeric portal.
Activate the Norkantas portal.
Activate the Grandfall portal.
Complete the quests related to the Scabonzis.
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 paddock.
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.
Enter Giltanbourg.
Complete the Alchemy Learning Quests.
Complete the Lithofortress.
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.