Pack Tactics. The soldier has advantage on an attack roll against a creature if at least one of the soldier’s allies is within 5 feet of the creature and the ally isn’t incapacitated.

Undead Fortitude. If damage reduces the soldier to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the soldier drops to 1 hit point instead.

Multiattack. The soldier attacks three times with one of its weapons.

Halberd. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 9 (1d12 + 3) slashing damage

Dimensional Shackles. The Undead Gate Keeper can point to one creature of its choice. The targeted creature must succeed a DC 14 CON saving throw. On a failed saving throw the target creature is shackled by spectral chains and takes 5(2d4)bludgeoning damage. The creature's speed is also reduced by half and cannot jump. On a succeded throw only half damage is taken.

Parry. The soldier adds 3 to its AC against one melee attack that would hit it. To do so, the soldier must see the attacker and be wielding a melee weapon.