LitRPG spartan warrior system apocolypse

Cecis, a brave Captain of a Spartan soldiers' company, finds himself standing on a treacherous battlefield against a massive army of Persian invaders. His troops are valiantly fighting, but they are outnumbered and outmatched, and the outcome of the battle seems inevitable. As Cecis prepares for the worst, something extraordinary happens. A strange, ethereal "system" emerges before him. Suddenly, he is whisked away to a mysterious "tutorial" where he discovers that through the system anyone can master magic and vastly enhance their physical powers to an extent thought impossible before.