Here is the full list of all 27 Peregrin achievements.
Discover all investigation points
Complete the Chapter 5 plane flame puzzle first try
Make your way across Chapter 3's crucibles with 15 or fewer button presses
Complete the Chapter 3 generator puzzle first try
Complete Chapter 1 without dying
Reach the final monolith
Activate the last totem in your journey
Reach the fifth monolith
Reach the fourth monolith
Reach the third monolith
Kill an enemy using a sentry turret in Chapter 5
Possess a creature 100 times
Clear a battle zone using only a single heavy enemy
Possess every possible creature
Reach the second monolith
Give yourself the upper hand in Chapter 2's final battle
Activate 20 totems
Possess a creature 50 times
Reach the first monolith
Die 5 times
Activate 10 totems
Use a light enemy to kill a ranged enemy
Spend 60 seconds on a single vista scene
Activate 5 totems
Possess a creature 10 times
Force an enemy to kill their ally
Discover an investigation point