Level 3, it's easy to miss on the level up option, it's a single checkbox immediately above the invocations checkboxes I think
EDIT: also, Imps should have 120ft darkvision, so sort of. Devil's Sight is meant to penetrate magical darkness but apparently doesn't at the moment.
Technically neither does devil's sight as the invocation in game, its broken. also would prefer invocations of repelling blast and eldritch spear.
