The Fendel Army were (at first) the primary villains in Tales of Graces F. They were soldiers whose goal was to maintain the power of their cryas in order to stabilize their country.
After the childhood arc, it was mentioned in a letter from Asbel's mother that Llant has been facing difficulties due to Fendel frequently piliaging the town. Lord Aston, Asbels dad, was apparently killed by one of the soldiers. When Asbel and Cheria came back to their hometown, they heard from Bailey that Frederic was kidnapped. After recovering him, the Fendel Army came in with a few giant fighting-machines; Asbel and Cheria led them to the cliff at Llant Hill and only a few of them fell off. Just when they were about to get blasted, Sophie appeared and helped then stop the machine. Later, they planned to do a suprise attack at their basecamp the following night; however, the soldiers took advantage of their "suprise" by pilaging Llant, only to be driven off by Hubert and the Strathen Army.
Later on, while Asbel and the group planned on entering Fendel themselves to get to the fire valkines, their spy was kidnapped by a Fendel Captain at Riot's Peak. After defeating them, the captain and his gang tried to draw their weapon, but they were killed off by one of the three gaurdians due to the fact that "It was forbidden to draw a weapon after a match". In Fendel, it was heard that they planned on doing an experiment on the fire valkines to really help maintain their cryas. Pascal mentioned that it would be extremely dangerous due to it having the most unstable eleth that could blow up the whole country. The experiment was being led by Kurt Bessel, Malik's old best friend from 20 years ago. After fighting Kurt near the valkines, the experiment began to go out of control. Pascal attempted to step in, but Kurt decided to sacriface himself due to it being his fault. He destroys the power cord to stop the experiment, which severely electricutes him and dies. Shortly afterwards, "Richard" swooped in and drains all the fire eleth from the valkines and briefly fought Sophie.
Eventually, when Lambda's monsters roamed around the world, the Fendel Army had no choice but to work together with Windor and Stratha. In the end of the future arc, it can be implied that Fendel began to be a peaceful country again.