Cloud knight (stewards of the eternal throne)

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

Innate Spellcasting. The knight's innate spellcasting ability is Charisma. It can innately cast the following spells, requiring no material components:

At will: detect magic, fog cloud, light

3/day each: feather fall, invisibility, misty step, telekinesis

1/day each: control weather, gaseous form 

Flyby. The knight doesn't provoke an opportunity attack when it flies out of an enemy's reach. 

Multiattack. The knight makes two morningstar or Longbow attacks.

Morningstar. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 21 (3d8 + 8) piercing damage.

Longbow. Ranged Weapon Attack: +10 to hit, range 300/1200 ft., one target. Hit: 20 (3d10 + 5) piercing damage. 

Change Shape. The knight magically transforms to look and feel like a Beast or a Humanoid it has seen or to return to its true form. Any equipement the knight is wearing or carrying is absorbed by the new form. Its statistics, other than its size, don't change. It reverts to its true form if it dies.

Cloud Smite (Recharge 5-6). 

Until the end of its turn, the knight's melee attacks each deal an extra 14 (4d6) thunder damage and the target must succeed on a DC 15 Constitution saving throw or be stunned for 1d4 turns