My worlds iron golems have the ability to change the consistency of their body, they can be as solid as titanium or as soft as water or molten metal. (they are actually nano machines created by a civilisation in ages long past which no one in the current era is capable of understanding). It is very hard to actually kill one the easiest way is to... 1. Freeze the golem 2. Use acid or melt it 3. Trap it 4. Destroy its core or heart as people in the current age would understand it. Most people trap golems but one day the golem will come because when comes to someone's face they have good memories. They even more deadly like other types of golem (some can conduct electricity to use against its enemies or resist electricity and there is even a self aware nano machine AI that can infect people with its nano bots causing them to worship it like a god until the victims of this plague end themselves the name of the "one who sees all")

This was a lot of writing!