Here is the full list of all 8 Firebird - there are La Peri achievements.
Keep the flower for yourself and become immortal.
Steal the petal from the air avatar.
Steal the petal from the water avatar.
Steal the petal from the earth avatar.
Get backstage and find Iskender’s entrance with your flashlight.
Renounce immortality and preserve the Péri’s dance.
Discover all illustrations in the ancient book of La Péri.
Unlock all the achievements.