The Merc Whistle is a special gift in Fire Emblem Warriors: Three Hopes that can only be given to allies with an A Support Level with Shez. Players will receive the whistle automatically after reaching Chapter 10, and they can use it as a single-use gift for one character per playthrough. Giving the Merc Whistle will unlock some bonus dialogue with the particular character in Fire Emblem Warriors: Three Hopes, yet this is not the only benefit players will receive when gifting the Merc Whistle.
The character who receives the Merc Whistle will repay the protagonist with an equipable accessory that will switch Shez's special ability to that of the unit. For example, giving the whistle to Annette will grant the player the accessory, Wooden Doll. Accordingly, equipping this doll will allow Shez or anyone to use the ability «Courageous Aria,» a skill that fills the Unique Ability Gauge during combat and can be used to increase the damage output of the caster and allies.
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As mentioned above, the Merc Whistle can only be given to a single ally during a playthrough. However, with the NG+ feature in Fire Emblem Warriors: Three Hopes, players can carry over their equipment and items into the new game, allowing them to retain the keepsake that changes the protagonist's Action Ability in Fire Emblem Warriors.
Undoubtedly, the best character to give the Merc Whistle is Byleth, a unit that Shez will encounter quite late in the game's story. She will repay the protagonist with the Tactics Primer, an accessory that unlocks Divine Pulse, one of the best attacks in the game. When cast, Divine Pulse will freeze time for all nearby enemies for up to 20 seconds, allowing
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