Merrow Voicemaster (Berserk Supplement)
From D&D Wiki
Medium humanoid (Merrow), any alignment
Saving Throws Dex +7, Wis +4, Cha +6
Amphibious. The merrow can breathe both air and water.
Fin. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) bludgeoning damage.
Merrow's Song (Recharge 4-6). Any creatures of the merrow's choice within a 30 ft. cone centered on the merrow must attempt a DC 14 Dexterity saving throw. On a failure, they take 10 (4d4) thunder damage and 10 (4d4) psychic damage, and are stunned until the end of your next turn.
Leadership (Recharges after a Short or Long Rest). For 1 minute, the merrow can utter a special command or warning whenever a nonhostile creature that it can see within 30 feet of it makes an attack roll or a saving throw. The creature can add a d4 to its roll provided it can hear and understand the merrow. A creature can benefit from only one Leadership die at a time. This effect ends if the merrow is incapacitated.
The strongest among the merrow, voicemasters have done battle numerous times. While still as graceful as any other merrow, they often lose their playfulness, becoming much more stoic and and almost eerily silent, even a single unrestrained murmur potentially harming anything close. They are among the few to disregard their culture's teachings on being wary of humanity, having the strength to destroy the very ship they interact with should the situation go sour. When merrow must do battle with sea gods, voicemasters head the charge.