So Goodrum and Shizzo are lower-level bosses, who is the big bad boss to fight at the end? Ron, hurling orange chicken? OMR with "Pwning Level" = 9000? Princess L with a death of 1000 cutting remarks?
How does Joon fit into the game?
You will face Joon first in Act 1, then later on in Act 3, and finally in Act 5.
You can avoid facing the Bosses OMR and Princess L, depending on the choices you make.
(Playing an evil character, ie doing bad choices will definatly create attention to OMR and Princess but you can bypass those obstacles).
Final fight is with King Ron Avidan of course, and it's not an easy fight you can finish in 30 mins.
It's an ongoing fight lasting 12 hours, so it's not for the weak.
if you fail (do a single mistake ie losing rhythm at the Mirage Ice-Machine), you'll have to start the fight over again (another 12 hours minimum to be able to defeat him).
Not for the faint of heart or for those with lives.