Here is the full list of all 49 VALKYRIE ELYSIUM achievements.
Completed Seraphic Gate
Defeated Odin
Defeated Fenrir
Obtained every Hollow Blossom
Obtained every Verdant Blossom
Completed Chapter 9
Agreed to Armand's offer
Unlocked all terms
Completed the game on Normal difficulty
Completed all subquests
Learned every Divine Art
Learned all of Valkyrie's skills
Completed Chapter 8
Learned every Einherjar attack and their normal attacks
Unlocked all Einherjar memories
Landed a Soul Burst Level 3 attack
Landed a Soul Steal in midair
Completed Chapter 7
Completed 20 subquests
Completed Chapter 6
Obtained every weapon
Completed 10 subquests
Completed Chapter 5
Raised the Combo Gauge to 300 Hits
Completed Chapter 4
Obtained a Verdant Blossom
Completed Chapter 3
Obtained a rune
Completed Chapter 2
Unlocked an Einherjar memory
Purified a monster by pushing them into a hole or off a cliff
Obtained
Completed a subquest
Completed Chapter 1
Purified a Naglfar
Obtained a Hollow Blossom
Completed the tutorial
Purified a monster
Defeated two monsters with a single Lightning Bolt
Completed every ending
Landed a Nibelung Valesti I attack
Obtained every rune
Upgraded every weapon to its full potential
Reached SSS proficiency with every weapon
Completed the game on Hard difficulty
Unlocked every achievement
Completed Hilde's Vengeance
Completed the game on Valkyrie difficulty