Evasion - If Zud is subjected to a DEX saving throw, the retired adventurer takes half damage on a fail and no damage on a success. 

Keen Seneses - Zud has advantage on all WIS (perception) checks. 

Mimicry - Zud can mimic the sounds of anything he has heard throughout his long life. The creature that hears these sounds will be able to know that it is fake if it successfully passes a WIS (insight) check (DC = 18)

Multiattack. Zud makes 3 attacks, 2 with his Dagger of Death and 1 with Lethal Feathers

Dagger of Death. Melee Weapon Attack: +15 to hit, reach 5 ft., 1 target. Hit: 16 (4d4 + 8) [Piercing] damage.

Lethal Feathers. Zud leaps into the air and opens his wings, releasing a volley of razor sharp feathers. Anyone within the 45ft, 90-degree cone needs to make a DEX Saving Throw (DC = 18) or take (8d8) [slashin] damage or half as much on a save. 

This Bird Isn't Done Yet. As a Bonus Action, Zud can move up to half his movement speed. As he moves, Zud opens his wings, revealing their sharp edges. If he moves through any amount of creatures, they must make a DC = 16 DEX Save to avoid taking (4d6) [Slashing] Damage. 

Tear Through The Cloudless Night. Zud drops a smoke bomb 5 ft in front of him. The smoke bomb explodes and covers a 25 ft radius where it was dropped. Zud has perfect vision through this smoke, but his enemies do not. This smoke lasts for 2 rounds unless dispearsed.