Demi fiend in Digital Devil Saga. i still haven't beat that guy...

final boss of heavenly sword ... had to see some tips on youtube...

dude it seems all your familly are super starts... your sister in law is a supermodel, your brother is a professional boxer with cat reflexes.... Oh well we can see who got left out in the familly!!

kidding asside... mike wasn't that hard...

and lu bu... did you try to beat him with a brand new character only? cause once you're a little beffed, he's one of those 2 shots dudes (ok it's a bit more but still...)

Tell me about it, we spent more time learning him than we did on the entire MC BWL and the rest of AQ combined. Even when the steps are explained in minute detail, someone always eats the freakin insta beam of death, at least one idiot dps always dies inside his stomache and someone is always in the space you're suppose to be in because they can't remember where they're suppose to be.

I had trouble with Ganon... my sis told me it was because I didn't have the wooden sword anymore.... so I redid the whole game without upgrading.... he was easy as heck once I arrived to him! thanks sis!! (the real deal was the blue knights)

For me it'd either be the first time I had to fight Alma from Ninja Gaiden on the Xbox or the final "boss" in Ninja Gaiden 2. Also throwing in what Mendicate Bias already said. That stuff was crazy hard.

I suppose killing the Prophet of Regret on Legendary in Halo 2 could be difficult as well with all the honour guards and one hit kills but I found a trick making it easy after the second time I played that part.

I feel like taking something from Ninja Gaidan is cheating for this list. Ninja Gaidan is synonymous with "impossibly difficult". So I guess thta means I agree.

Also, I'd like to add to that, there was one spot in Halo 2, on Legendary, that was insanely difficult if you were going solo. It was actually the first level, this endless Elite spigot where you were virtually out of ammo by the time they were all dead. It was so hard... I felt like I blitzed the next few  hours of the game easily when I finally passed it...

I've never been able to beat Seymour in FFX...

I will one day, eventually, when I find my copy of the game...

Killzone 2, Elite, Radec

I'm not sure.
Borgan from (the original, Sega CD) Lunar EB was pretty hard. Damn gravity bombs every turn.