Undead Fortitude. If damage reduces the zombie 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 zombie drops to 1 hit point instead.

Longsword. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (1d8 + 2) bludgeoning damage.

Call to Serve. Ability. Range: 60ft. The Zombie Captain can turn one dead creature it can see within range into an undead creature that regains 1/2 of the original hit points and can attack, but cannot cast spells, even if it was a spell caster before death. The creature also gains a vulnerability to radiant damage and an immunity to poison damage and being poisoned. This ability cannot affect undead.