So at what point should you fight the Dark aeons?

[KLightningflik]

I'm at the end of the game now and just got all the celestial weapons, and now I'm grinding and doing Monster arena stuff. Grinding Don tonberry for AP, etc. I can kill most enemies with a single attack now. The Dark aeons still kill me instantly though...do you need to fill most of the sphere grid before your stats are high enough to survive?

[Purplefairy22]

I waited a little too long TBH. I had a mere 4000 hp tops but every other stat at 255. Valefore to Shiva were a doddle.

Bahamut was still a problem tho, Impulse and 20 000 DMG with a punch saw me scarper.

[Terra]

There's two ways to tackle the Dark Aeons

Grind until you can survive their attacks.
or
Use Aeons to take the hits for you, and go glass cannon.

[KLightningflik]

I guess I'm mostly worried about becoming too strong through grinding and not having a fair fight with them.

[gecko]

Honestly, there isn't really a "right moment" for the last few of them. The increase in their Luck stat means you're not gonna be able to hit them consistently without having at least 80+ Luck yourself, if you can grind that at a fair pace then you're maxed on all of the stuff that matters and strategy has already devolved to Ribbon/Stoneproof+Auto-Phoenix+Auto-Haste armor with Quick Hit spam all the way. Forget about healing (other than Auto-Life), AP will take care of it without using a turn.

This starts at Shiva, though Shiva's still quite beatable even if you miss most of the time.