The Heroic Legend of Arslan

is a Japanese fantasy novel series written by Yoshiki Tanaka. It started to be published in 1986 and as of 2016 there are 15 novels and one side story in the official guidebook Arslan Senki Tokuhon.

It was adapted into a manga, which caught up with the novel and then received an original ending, and ran from November 1991 to September 1996. It also received two anime film adaptations, and a four-part, unfinished anime OVA. In 2013, a second manga adaptation started serializing at Bessatsu Shōnen Magazine, with illustrations by Hiromu Arakawa. An anime television series based on the Arakawa manga aired in 2015. A second season aired from July 3 to August 21, 2016.

Plot
The story follows the exploits of Arslan, the crown prince of the fictional kingdom of Palse, which is taken over by the neighboring nation of Lusitania after his father, the king Andragoras, falls victim of a treacherous plot led by one of his most trusted retainers. After barely escaping with his life, Arslan rejoins his loyal servant, Daryoon. Backed up by only a few more companions, including the philosopher/swordsman/tactician Narsus and his young servant Elam, Pharangese, an aloof, cold priestess and Gieve, a travelling musician and con-man, Arslan must stand against overwhelming odds to assemble an army strong enough to liberate his nation from the Lusitanian army which is led by the elusive warrior known as "Silvermask".

Other Sources
Wikipedia