rugby football is a very violent game!
Rugby is a very old game that can be traced all the way the Greek and Romans.
Wow!   What was the ball made from back then?
My guess out of the some kind of animal hide.   Rugby is still favorite game in English public school. 
What are some of the positions called?
You got the kickers and the defenders.  There are different variations of football know as football codes.
what are some of those codes?
You got football in Australia refers to football codes as  Australian rules football.