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