William Viana is a Brazilian voice actor, dubbing director, and adapter known for his extensive work on anime series and films for the Portuguese market. Born William Viana Schuler on April 17, 1990, in Porto Alegre, he has built a career spanning performance and creative direction.

Viana has lent his voice to a wide array of characters across numerous popular anime franchises. Among his noted roles are Kentarō Yamamoto in Back Street Girls: Gokudols, the modified form Ultimate Mechamaru in Jujutsu Kaisen, and Shūgo Amihama in the water polo anime RE-MAIN. He also voiced the character Hou in Love of Kill, Thomas Taurus, also known as He Is Thomas, in Tiger & Bunny 2, Dubs in The Seven Deadly Sins: Cursed By Light, and Minoru Kagamari in the JoJo's Bizarre Adventure OVA series Thus Spoke Kishibe Rohan. His film work includes roles in Jujutsu Kaisen 0 as Mechamaru and Black Clover: Sword of the Wizard King as Nacht Faust.

Beyond these, Viana's voice can be heard in several other high-profile productions. He is the Portuguese voice of Natsu Dragneel for the first 72 episodes of Fairy Tail and its related film, a character he has expressed a deep personal connection to. He also voices Youichi Hiruma in Eyeshield 21, Roy Mustang in the Funimation dub of Fullmetal Alchemist: Brotherhood, Guido Mista in JoJo's Bizarre Adventure: Golden Wind, Geordo Stuart in My Next Life as a Villainess, and the Emperor Kaido in a new dub of One Piece.

In addition to his on-screen roles, Viana frequently works behind the scenes as a dubbing director and script adapter. He has directed the Portuguese versions of numerous anime, including Love of Kill, Rent-A-Girlfriend, My Next Life as a Villainess: All Routes Lead to Doom!, and the Funimation dub of Cowboy Bebop. He also served as an ADR director on early episodes of Fairy Tail and on Fullmetal Alchemist: Brotherhood. His work on the series Love of Kill was conducted at the Som de Vera Cruz studio in Rio de Janeiro.