Pious Offering reads:
“Judgement now also consumes a percentage of your current mana and deals more damage (multiplicative with other modifiers) per mana consumed.”
Notably, this additional mana “consumption” does not apply to Font of the Erased legendary ring and Crushing Blows, a Forge Guard passive. These read, respectively:
“X% of mana spent gained as ward”
“Increased damage per 1 mana cost: X% per point”