It's optional. Simply head east until you meet the Moogle leader to do the required portion of the game.

Alternatively, make sure you can actually kill Bombs, and have enough HP, more than 2000 should do it (which means you'll be 40 or higher). Chain your Quickenings together by mashing the R2, Triangle, Square, and X buttons as quick as you can (don't be an idiot and wait for them to show up just by pressing each button once).

Your friend is an idiot, no offense. If he is able to Renew more than once during your fight, you aren't ready, unless you can stand long enough. There are instances in which he uses Renew up to fifteen times (this happened to me), so don't count on the King stopping in order to defeat it.