en_tn/2ch/13/17.md

killed them with great slaughter

This idiom means that they thoroughly defeated them, or that they killed very many of the soldiers. AT: "thoroughly defeated them" or "slaughtered many of their soldiers" (See: rc://en/ta/man/translate/figs-idiom)

500,000 chosen men

"five hundred thousand chosen men." The phrase "chosen men" is an idiom that refers to elite soldiers who were skilled in battle. AT: "500,000 of the best soldiers" (See: rc://en/ta/man/translate/translate-numbers and rc://en/ta/man/translate/figs-idiom)