Final Fantasy XIII Final Boss Help *SPOILERS*

I can defeat the final boss... but I am having a very hard time five-starring his last form(Which I need to do). What are your recommended strategies? If you need any additional information including stats, weapons, etc., feel free to ask. Thank you all in advance.

I'd say try and get an ultimate weapon for whatever characters you're using since that will let you access the 6th stage of your ATB gauge. Also update the crystalarium as far as possible or atleast pretty far and unlock all four accessory slots. Then go all out all aggressive of the final form and it should be pretty easy to beat.

I got five stars with my crystalarium at max for the three main states of all my characters and I had the three non-main states at the last stage. Plus, I had starred level 2 weapons. This was my first time fighting the boss so I didn't have the 10nth stage of the crystalarium and I was on easy but I was able to beat and 5-star the final boss with hardly any healing. Seraph's Crowns are great to have when going through the instant death move part of the final boss.