Here is the full list of all 50 Apocalypse Knights 20 - there are The Angel Awakens achievements.
Character level reaches 100
Kill 10000 Raptor demons
Own 5 Lances
Kill 10000 FaceCube demons
Level 10 difficult all pass
Get 100 perfect wave
Level 9 difficult all pass
Level 8 difficult all pass
Level 7 difficult all pass
Level 6 difficult all pass
Level 5 difficult all pass
Kill Fire Devil
Get 30 perfect wave
Own Centurion Set
Kill 100 Raptor demons
Kill 100 FaceCube demons
Character level reaches 50
Own Nightmare Set
Level 4 difficult all pass
Level 3 difficult all pass
Kill 10000 demons
Own Ghost Set
Own Bloodlust Set
Level 2 difficult all pass
Own Templar Set
Own Alloy Set
Own 5 armors
Own Crusader Set
Save 100000 coins
Own Steel Set
Own 5 Broadswords
Own Imperial Set
Kill 1000 demons on a horse
Own 5 Spears
Kill 1000 demons with Lance
Own 5 rides
Own Demon God Set
Level 1 difficult all pass
Pass 60 Waves in a row
Character level reaches 30
Pass 40 Waves in a row
Kill 1000 demons with Spear
Kill 100 demons with Ultimate Skill
Kill 1000 demons with Broadsword
Kill 1000 demons
Pass 20 Waves in a row
100 combos
Kill 500 demons
Character level reaches 10
Kill 100 demons