Dead Ambusher. The skeleton archer has a +3 bonus to Initiative rolls and cannot be surprised.

Archery. The skeleton archer has a +2 bonus to attack rolls it makes with ranged weapons.

Sharpshooter. Attacking at long range doesn't impose disadvantage on the skeleton archer's ranged weapon attack rolls. Furthermore, the archer's ranged weapon attacks ignore half and three-quarters cover. Lastly, if the archer make an attack with a ranged weapon that it is proficient with, it can choose to take a -5 penalty to the attack roll. If that attack hits, it adds +10 to the attack's damage.

Shortsword. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) piercing damage.

Longbow. Ranged Weapon Attack: +8 to hit, range 150/600 ft., one target. Hit: 8 (1d8 + 4) piercing damage.

Flaming Arrow. Once per combat and as a bonus action, the skeleton archer can light one of its arrows on fire, making its next longbow attack deal an additional 2d4 fire damage.

Poisoned Arrow. Once per combat and as a bonus action, the skeleton archer can coat one of its arrows with poison, making its next longbow attack deal an additional 1d6 poison damage and force the target to make a DC 12 Consitution check. On failure, the target is Poisoned for 1 minute and repeats the saving throw at the beginning of each of its turns until it succeeds.