Why do all ISIS fighters have names like Abu X al-X?

I know I am quite late but a saudi friend explained me that it means they are fathers of a boy. abu means father. the second name is the name of their first (male) son. and then we either have their real surnames or invented ones which indicate their country of origin (al kurdi, al britani etc ). read more

The founder of ISIS: Abu Musab al-Zarqawi Current Leader of ISIS: Abu Bakr al-Baghdadi. They are not related but the name Abu is common in Muslims. Just like the name John , Abu is a common name. That’s it. read more

Abu basically means "father of" and is commonly followed by the name of their first born son or an attribute the person is known for. Most Jihadis use it to hide their real identity and generally make up their own and isn't necessarily an attribute or the name of their eldest son. read more