The official Fairy Tail website has shared the voice actors portraying the Alvarez Empire military in the series' next arc. Here are the actors and their roles:
August, Magic King and one of the Alvarez Empire military's Spriggan 12 - Yoshito Yasuhara
Invel, Winter General and a Spriggan 12 - Tomoaki Maeno
Brandish, Country Demolisher and a Spriggan 12 - Manami Numakura
Dimaria Yesta, Valkyrie and a Spriggan 12 - Natsumi Fujiwara
Ajeel Raml, Desert King and a Spriggan 12 - Hiromichi Tezuka
Marin Hollow, member of the military's Brandish Squad - Tomohiro Yamaguchi
Shinji Ishihira is directing the final season, Shouji Hata is the sound director and Yasuharu Takanashi produces the music. HIro Mashima is the original creator and he is helping with development. The opening theme is power of the dream by lol and the ending theme is Endless Harmony by Beverly.
The voice cast remains the same:
Tetsuya Kakihara as Natsu Dragneel
Sayaka Ohara as Erza Scarlet
Yuuichi Nakamura as Gray Fullbuster
Aya Hirano as Lucy Heartfilia
Rie Kugimiya as Happy
Satomi Sato as Wendy Marvell
Yui Horie as Carla
The manga series with the same title is written and drawn by Hiro Mashima, published by Kodansha, Del Rey Manga and Kodansha USA have the English license and Weekly Shonen Magazine serialized it. The manga ran from August 2, 2006 to July 26, 2017 with 63 volumes and there is another manga series publishing right now. Fairy Tail 100 Years Quest is the sequel to the original manga series, written by Hiro Mashima and illustrated by Atsuo Ueda. It has been running from July 25, 2018 in the Weekly Shonen Magazine and Magazine Pocket.