The Olympic Heroes of Supreme Justice

This sci fi historical fiction book is set in the year of 489 B.C.E. when the Persians intend to invade Greece through the Salamis, Thermopylae and...FROM SPACE! At least their extraterrestrial allies will be doing that. To counter this, cosmic heroes, that work for a universal organization, will be aiding the Greeks to repel 2/3 of these invasions. The one from space, and the other in the Salamis. Since, there are extraterrestrial forces aiding those invasion forces, some being members of the heroes' species; and the code of the "Infinite Supremes," or the cosmic heroes, allows them to partake in war only when there are unnatural and/or supernatural advantages on one side. Because they don't want to be aiding "man's campaign" unless there's a justifiable reason. The leader of the Persian Empire, Xerxes, is desperate to dominate and conquer Greece. He seeks to strike his iron fist into Greece hard, but the Olympic Heroes are determined to repel a majority of his invasion forces. They're willing to do all they can to help the Greeks neutralize the Persians and their allies to ensure Greece is safe.