The The Gloom Below Add-on for The Chant has 8 achievements.
Craft the Iridescent Blade and Throwing Plasma
Find 11 Lore pickups in The Gloom Below
Charge all 6 Prisms
Destroy all Maws
Escape the Gloom Dimension
Hit 4 enemies simultaneously with Throwing Plasma bolts
Kill 2 or more enemies with one Iridescent Blade Explosion
Upgrade prism abilities 12 times in one life