Warden

Keen Smell. The Warden has advantage on Wisdom (Perception) checks that rely on smell.

Limited Tremorsense. A creature can pass through the Warden's tremorsense range without being detected by passing a Dexterity (Stealth) check contested by the Warden's Passive Perception.

Limited Blindsight. The Warden's blindsight comes from its sense of smell. If a creature ends its turn within the Warden's blindsight radius, the Warden detects it.

Sensitive Hearing. When the Warden takes 10 Thunder damage or more from a single attack, it becomes deafened, disabling its tremorsense until the end of its next turn.

Darkness Aura. The Warden emits a 60 ft. radius sphere of magical darkness centered on itself.

Unusual Nature. The Warden doesn't require food, drink, or sleep.

Slam. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 22 (3d10+7) bludgeoning damage.

Sonic Boom (Recharge 5-6). The Warden emits a 5 ft. wide, 50 ft. long sonic boom. All creatures caught in this blast must make a Constitution saving throw (DC 18), taking 26 (4d12) Thunder damage, or half as much on a successful saving throw. The blast passes through walls and other obstacles, but is halted by an area of Silence.