Grand Arbiter Augustin IV [The List] BW005 You’ll find the full rules

You’ll find the full rules for the Primaris Librarian in Phobos Armour in Codex: Space Marines

Set: Black & White: Plasma Freeze Type: Water Rarity: Holo Rare Retreat cost: Colorless

While it's phased out

Set: POP Series 9 Type: Colorless Rarity: Rare

Grand Arbiter Augustin IV [The List] BW005 You’ll find the full rulesSet: The List Type: Legendary Creature Human Advisor Rarity: Rare Cost: {2}{W}{U} White spells you cast cost {1} less to cast. Blue spells you cast cost {1} less to cast. Spells your opponents cast cost {1} more to cast. The Arbiter is a conduit of justice, a will so disciplined that it dispenses justice without ego or remorse.