Here is the full list of all 39 Shiness: The Lightning Kingdom achievements.
Beat a legend with rank S
Achieve rank F 10 times
Solve the puzzle in the Room of 9 Pillars
Reach level 50 with every character
Collect 100,000 Uzu
Acquire the Hunting Shoes
Help the Sister of Secrets
Break free of Ayron
Have 5 characters in your team
Unlock all Spells
Defeat Mother
Beat one of each kind of enemy
Acquire an Amos
Spend 100,000 Uzu
Catch one of every wildlife
Get knocked out 50 times
Inflict 100 guard breaks
Have Irys decrypt a Lightning Shi
Have Kaorys decrypt a Plant Shi
Achieve rank S 100 times
Win 100 combats without using magic
Create 10 Recipes
Trigger 50 traps
Defeat an enemy using Engagement only
Defeat Meos
Kill an enemy with the Hyper attack
Capture 50 wildlife
Honor a Contract
Drop down to 1 HP
Discover 10 Interest Points
Finish a fight without getting hit
Defeat Irys
Defeat Kaorys
Win 100 combats only using magic
Finish all secondary quests and all contracts
Discover all of Rosalya’s doors
Win 50 fights without getting hit by the enemy
Reach Adorya station without setting off a single alarm
Finish the game (with NO Game Over)