Here is the full list of all 31 Aegis Defenders achievements.
Complete an entire area without dying
Defeat the (KS) Breath Dragon
Earn 50 RP from Dialog Choices
Complete Area 2
Kaiim Joined the Party
Collected 15 Relics
Defeat the Zanoh
Purchase 5 items
Killed 300 Enemies
Complete Area 1
Killed 200 Enemies
Discovered Aegis
Collected 5 Relics
Killed 100 Enemies
Bart Joined the Party
Clu Joined the Party
Complete Area 3
Complete Area 4
Complete Area 5
Complete Area 6
Zula Joined the Party
Collected All the Relics
Defeat the MadXArmor
Complete Game on Hard Difficulty
Complete Game on Insane Difficulty
Purchase 15 items
Purchase all items
Complete the game without dying
Obtained The Blood of A God
Rescued Shreya
Found Kobo and the Clarent