Amphibious. The koalinth can breathe air and water.
Martial Advantage. Once per turn, the koalinth can deal an extra 7 (2d6) damage to a creature it hits with a weapon attack if that creature is within 5 feet of an ally of the koalinth that isn't incapacitated.
Trident. Melee or Ranged Weapon Attack: +3 to hit, reach 5 ft. or range 20/60 ft., one target. Hit:4 (1d6 + 1) piercing damage, or 5 (1d8 + 1) piercing damage if used with two hands to make a melee attack.
The koalinth, found in Danger at Dunwater, are martial and aggressive aquatic hobgoblins, with brightly colored faces and functional gills. They are known for their ferocity, and for their hatred of elves.