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