Mashima serialized Monster Hunter Orage, an adaptation of the Monster Hunter video games, in Monthly Shōnen Rival from 2008 to 2009. Also in 2008, he drew a remake of Atsushi Kase's gag manga Chameleon for the 50th anniversary of Weekly Shōnen Magazine.
Mashima listed Akira Toriyama's Dragon Ball as his favorite manga growing up, the video game series Dragon Quest, and Yudetamago's Kinnikuman as inspiring him to become an artist. He also read/watched several works by Hayao Miyazaki as a child. In 2008, when asked if there were any current things that inspired him, he gave Code Geass as a response. In 2011, Berserk was stated to be his favorite manga.
Mashima had six assistants in 2008 that worked in an 8,000 sq. feet area with seven desks, as well as a sofa and TV for video games. He revealed his schedule for Fairy Tail was script and storyboards on Monday, rough sketches the following day, and drawing and inking Wednesday through Friday. The weekend was for Monster Hunter; working on a quarter of the story each weekend and finishing by the end of the month. In 2011, he stated that he worked six days a week, for 17 hours a day. Mashima's assistants included Miki Yoshikawa, who has gone on to work on the romantic comedies Yankee-kun and Megane-chan (Flunk Punk Rumble) and Yamada-kun and the Seven Witches. In 2008, together they developed a crossover one-shot story called Fairy Megane where characters from Yankee-kun decide to find part-time jobs at the Fairy Tail guild. Other assistants who have gone on to work on projects of their own were Shin Mikuni, who published Spray King, and Ueda Yui, who published Tsukushi Biyori.