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.   If the Zombie Defender loses its shield, it loses the following abilities, actions and reactions: Shield Bash, Sentinel, Shield Slam, Defender.   Shield Bash. If the Zombie Defender moves at least 10 feet straight toward a target and then hits it with a Shield Slam attack on the same turn, the target must make a DC 12 Constitution saving throw. On a failed save the target is pushed back 10 ft and falls prone. On a a succesfull save they are not pushed or fall prone.   Sentinel. When the Zombie Defender hits a creature with an opportunity attack, the creature's speed becomes 0 for the rest of the turn.