Riffler

The riffler can smell the presence of magical cards, including Decks of Many Things and other magical decks, within 1 mile of itself. It knows the direction to any such cards in that range. Effects that protect a target from divination magic block this sense.

The riffler can burrow through any nonmagical material that isn't iron, shuffling the substance through which the riffler moves aside like cards to form a tunnel that closes behind the riffler.

The riffler makes two Spectral Card attacks.

Melee or Ranged Spell Attack +6 to hit, reach 5 ft. or range 60 ft., one target. 8 (1d10 + 3) Force damage plus 5 (1d10) damage that is radiant if the d10 roll is an even number and necrotic if it's odd.

The riffler magically unleashes a spray of spectral cards in a 30-foot cone. Each creature in that area must make a DC 14 Dexterity saving throw. On a failed save, a creature takes 27 (5d10) Force damage and has the Restrained condition for 1 minute as cards bind it. On a successful save, a creature takes half as much damage only. A Restrained creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

The riffler casts the Plane Shift spell targeting only itself, requiring no material components and using Charisma as the spellcasting ability.

When a creature the riffler can see within 30 feet of itself makes an ability check, an attack roll, or a saving throw, the riffler can magically force that creature to roll a d6 and either add the number rolled to the total or subtract it from the total (riffler's choice), potentially changing the outcome.