Here is the full list of all 121 Onmyoji achievements.
Complete "Dreamland Encounter".
Complete "Netherworld Rift".
Complete "Underworld Judgment".
Complete "Upheaval".
Complete "The Way of the Onmyoji".
Complete "Resurrection of Orochi".
Complete "Perilous Ritual".
Complete "Secrets of Mt. Septem".
Complete "Orochi's Scheme".
Complete "Sleeping Puppeteer".
Complete "Heian Tales: Mujou Apprentices".
Complete "Heian Tales: Sakura Fest".
Evolve 10 shikigami.
Evolve 20 shikigami.
Evolve 50 shikigami.
Own 1 Lv. 40 shikigami.
Own 2 Lv. 40 shikigami.
Own 5 Lv. 40 shikigami.
Own 8 Lv. 40 shikigami.
Onmyoji reaches Lv. 60.
Feed 1 totem to Lv. 40.
Feed 2 totem to Lv. 40.
Feed 3 totem to Lv. 40.
Feed 4 totem to Lv. 40.
Clear a stage-10 Soul zone.
Clear stage 10 of any Evo zone.
Clear chapter 11 challenge in hard mode.
Clear chapter 12 challenge in hard mode.
Clear chapter 13 challenge in hard mode.
Clear chapter 14 challenge in hard mode.
Clear chapter 15 challenge in hard mode.
Clear chapter 16 challenge in hard mode.
Clear chapter 17 challenge in hard mode.
Clear chapter 18 challenge in hard mode.
Clear side-chapter 1 challenge in hard mode.
Clear chapter 19 challenge in hard mode.
Clear chapter 20 challenge in hard mode.
Clear chapter 21 challenge in hard mode.
Clear chapter 22 challenge in hard mode.
Clear chapter 23 challenge in hard mode.
Win 10 duel.
Win 30 duel.
Win 100 duel.
Add 50 friends.
Receive 100 heart from a friend.
Defeat a grade 5 Fire Kirin in a hunt.
Defeat a grade 5 Lightning Kirin in a hunt.
Make 50 donations in your guild.
Please accept this gift from us.
Own a grade 6 shikigami.
Win 50 realm raids.
Feed soul 100 times.
Clear a stage-10 Ultimate Orochi zone.
Win 6 Royal Battles.
Win 9 Royal Battles.
Win 12 Royal Battles.
Win 10 Royal Battles using only R shikigami.
Win 10 Royal Battles using only SR shikigami.
Win 10 Royal Battles using only SSR shikigami.
Win 20 Royal Battle duels using the exact same formation as your opponent.
Clear chapter 6 challenge in hard mode.
Clear chapter 1 challenge in hard mode.
Clear chapter 9 challenge in hard mode.
Clear chapter 10 challenge in hard mode.
Clear chapter 8 challenge in hard mode.
Receive 50 heart from a friend.
Own a grade 5 shikigami.
Clear chapter 5 challenge in hard mode.
Clear chapter 7 challenge in hard mode.
Find 20 shikigami shard zone.
Enter 20 shikigami shard zones.
Clear chapter 3 challenge in hard mode.
Clear chapter 4 challenge in hard mode.
Add 20 friends.
Complete "The Red Maple Forest".
Complete "Another Seimei".
Complete "Bows and Arrows".
Win 1 duel.
Defeat a grade 5 Wind Kirin in a hunt.
Defeat a grade 5 Water Kirin in a hunt.
Equip a grade 6 soul for the first time.
Complete "The Drunken Deity".
Learn all skills of any 1 onmyoji.
Complete "Sparrow Search".
Complete "Zashiki".
Complete "The Seer of Phoenix Forest".
Complete "Ame Onna on the Bridge".
Complete "Mt. Gloom Expedition".
Complete "A Dream Yet Not a Dream".
Complete "The Beautiful Carp".
Complete "Sakura and Momo".
Complete "An Unlikely Team".
Activate any 4-piece soul set stat.
Feed a soul to Lv. 15 for the first time.
Evolve 1 shikigami.
Upgrade a shikigami for the first time.
Learn a new onmyoji skill for the first time.
Clear chapter 2 challenge in hard mode.
Summon shikigami 10 times.
Summon shikigami 100 times.
Summon an SR shikigami.
Summon an SSR shikigami.
Find 1 shikigami shard zone.
Enter 1 shikigami shard zones.
Add 1 friends.
Receive 1 heart from a friend.
Login 1 day.
Login 2 day.
Login 3 day.
Login 4 day.
Login 5 day.
Login 6 day.
Login 7 day.
Login 8 day.
Login 9 day.
Login 10 day.
Own a grade 4 shikigami.