Who Is Praetorian Jack? His Backstory In Furiosa: A Mad Max Saga Explained 

To save you guys some time. He's the road warrior from Mad Max 2. He's the link between the old movies and the new. The legend of Max is like a religion based on travelers' tales. First people thought Jack was The Road Warrior, but then he died and and a younger man came and did crazier stuff. So they changed their beliefs and now the younger man is The Road Warrior, Mad Max. Why Mel Gibson didn't portray him this time could be one of many reasons, probably a combination. An incident happened a over a decade ago that gave him a bad reputation. He is also too old to have the same type of relationship with Furiosa as the one we saw in the movie, and George Miller also intended to cast a colored man as Jack in this movie, which suggests that he hates the idea of having an actor too closely associated with a role, and that Max could be anyone, like Spider-Man.

Wouldn't mind seeing a Praetorian Jack prequel.

I think it's interesting that Praetorian Jack acts a lot more like the old Mel Gibson version of Mad Max.

I like a new mad max movie with Mel Gibson to be main character

The Twist? Praetorian Jack is the REAL Mad Max!!! The other guy (Tom Hardy) stole his identity!