Promachos is a big word that describes a very important thing in ancient Greece. Promachos means "champion" or "protector".
Back in ancient Greece, they used to build big statues of their gods and other important figures. These statues were so big that they needed someone or something to protect them from bad guys who might try to damage or destroy them. That's where the promachos comes in.
A promachos was a warrior who was always ready to defend the statue they were assigned to protect. These warriors were usually very strong and brave, and they would stand guard near the statue all day and night. They might carry a big shield or a sword to fight off anyone who tried to harm the statue they were guarding.
Promachos didn't just protect statues either - sometimes they would also fight in battles to protect their city or their people. They were seen as heroes and respected by everyone.
So, to sum it up: promachos were really tough warriors who protected important statues and sometimes fought in battles to help their people. They were like superheroes of ancient Greece!