Sea Legs. The first mate has advantage on ability checks and saving throws to resist being knocked prone.
Multiattack. The first mate makes two attacks with its longsword.
Longsword. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit:6 (1d8 + 2) slashing damage, or 7 (1d10 + 2) slashing damage if used with two hands. If the target is a creature, the first mate can choose to deal no damage with the attack to disarm the target. The target must succeed on a DC 14 Strength saving throw or drop one item it is holding on the ground.
These no-nonsense sailors are the trusted allies of a pirate ship's captain. Ex-soldiers and trained mercenaries often find employment as mates aboard pirate ships. In The Sinister Secret of Saltmarsh, Bloody Bjorn serves as the first mate aboard Sea Ghost.