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.

Multiattack. The zombie elf makes one shortsword attack and one bite attack.

Shortsword. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) piercing damage.

Infected Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 2 (1d4) bludgeoning damage. Once bitten by a zombie, you must make a DC 13 Constitution saving throw or be infected. When infected, you must make a DC 13 Constitution saving throw round or take 1d4 necrotic damage.