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'
Recover all Nisshoku Daggers
Obtain all 'Yurei' medals in 'Nightfall'
Obtain all 'Kami' medals in 'Nightfall'
Complete Nightfall: Chapter IV
Complete Nightfall: Chapter III
Complete Nightfall: Chapter II
Kill two enemies at once with the help of Twin Shadow (Single Player)
Complete Nightfall: Chapter I