Here is the full list of all 33 Young Souls achievements.
Finish the game at least in Challenging mode
Defeat Dwarvengobben
Help the Professor to bury the Digger under rocks
Rescue the Professor
Complete the game at 100%
Kill Kah-Kon
Collect 25,000 gold
Kill Shinjo
Kill Dinkoy
Complete a dungeon without taking any damage
Open all gold key chests
Clear all hard branches
Open all silver key chests
Ride a dragon for the first time
Clear all Catacombs
Upgrade an accessory to its maximum level
Kill Fazmore
Beat Yarlanda in the last Mausoleum
Kill Tetcha
Open all bronze key chests
Upgrade a weapon or armor
Kill Marl
Equip an armor and helmet combo
Earn 5 stars on a Happy Fit training session
Beat Dinkoy
Block 10 attacks
Dodge an attack by rolling
Parry an attack
Kill a goblin for the first time
Upgrade a weapon to 6 stars
Collect 50,000 gold
Collect 100,000 gold
Finish the game in Expert mode