Ruby from FFVII... You only get one character, and he must have the proper Materia line-up, which is hard enough to get and level up to use multiple times. A lot must be done prior to actually thinking about stepping up to The Rube-Meister...
Omega from FFV won't stop handing my ass to me. >:T I could beat Ruby Weapon just fine, since I tend to become rather addicted to leveling up my characters and such. But in FFV...It takes fucking FOREVER to level up, and then I get bored and stop for a couple of days/weeks/months/etc.
I tried Omega from FF5 a few times, and I didn't get a single shot in. I can't begin to imagine the levels your characters need to be at in order to kill that godawful thing.
Dude, I played against Omega at level 99 with all 4 characters, he still kicked my ass. Let me say this, He isn't weak against Bolt 1 and 3. Bolt 2 and Flare are about the only useful spells (IMHO)
you've got to be kidding me! Nemesis was so damn easy >: O I beat him in seconds (thanks to Break-9999 damage limit)
You f'en retard the easiest way to beat it is by hitting it with Quick Hit, I already Know, I'm just saying its hard without Break Damage limit. All of my Aeons have every stat up, full hp, and every ability without using codes. I could beat him just with my Bahamut.
I can't remember if you ever get to fight Ultima Weapon from ff6 (or was it ?), but I seem to remember it being invincible to every attack I had at the time.
Also, some other contenders are ozma (ff9) and those damned giant tonberrys from ffx-2
It's times like these I'm glad I didn't finish FF3-6. I'm sure I would've tried to beat Omega and died several times. I would've ended up tossing something and breaking stuff. And the counselors would come again...
Emerald WEAPON from FFVII is 10x harder than Ruby.
The Time Devourer isn't that hard to successfully use the Chrono Cross on. It just takes fucking forever. You just need to be sure you've got a really even balance of every type of element available. You don't want to go in with a ton of greens and one red.
Beating that first Lavos isn't hard either if you're doing a New Game +. I've done it plenty of times on a + game.
Shit, Jess, I didn't even think to use Fire Rings against Omega. He'd always kill me with that fucking Atom Ray (or whatever the hell it was called) before I'd get a single shot in. Now I feel retarded.
I've also heard that Shinryu from FF5 is a pretty nasty boss. I never tried, though, because apparently the only weapon that does decent damage to him is the Dragon Lance, and I never found one of them. I tried stealing them from those Crystal Dragons for an hour or two and I kept getting shafted.