@Jarkes  
You can also steal at least four Dragon Lances from the Crystal Dragons in the first room after leaving the castle section. Shinryu only has around 50k HP and a character dual wielding Dragon Lances and using Jump will deal 9999 x2 damage in one go (x4 if they mastered Time Mage and can cast Quick to Jump twice). You’ll still need Coral Rings to survive his initial Tsunami though.

It’s the rainbow of light I tell you

@Description:
 
This is why you equip all four characters with Coral Rings before that. Mind you, he’ll STILL kick your ass with any of his other spells or attacks, but you can at least do that.
 
You know he’s tough when the most viable strategy for beating him (casting Berserk to prevent him from using his spells) can still caused you to get killed horribly quickly (Golem’s wall can pretty much only protect you from one attack, and you basically have to keep casting Golem while your other characters spam whatever super-powerful attacks they have).

@Diamond Dust  
Hard battle but Feral Chaos is more hardder epic battle and for the music outstanding

@Prof.NightJack  
Can’t escape!

@RainbowDashie41  
Reverse that. Chaos is canonically the worst endboss, but when it goes to the baddest mother in the room Shinryuu is the champ.
 
On the bright side- Fresh Ragnarok

@RainbowDashie41
 
Well, Shinryu’s plan in Dissidia was actually to have the unending strife caused by the war between Cosmos and Chaos shape the latter into the ultimate force of destruction for his own use.

that dragon belongs to him  

RUN!  
RUN!  
RUN!