The Nightfall Add-on for Aragami has 12 achievements.
Blind 4 or more enemies with a Shadow Grenade
Kill 4 or more enemies at once with the Explosive Kunai
Obtain all 'Oni' medals in 'Nightfall'
Complete Nightfall: Chapter IV
Obtain all 'Kami' medals in 'Nightfall'
Obtain all 'Yurei' medals in 'Nightfall'
Recover all Nisshoku Daggers
Complete Nightfall: Chapter III
Complete Nightfall: Chapter II
Complete Nightfall: Chapter I
Kill two enemies at once with the help of Twin Shadow (Single Player)