RUBY WEAPON
         Welcome to the worlds hardest boss of all time. Any of you unfortunate enough to run into his little red dick that he flashes from beneath the sand by the Gold Saucer should be well aware that this guy just flat out don't fight fair. First of all, you can't even touch him in the begining while he pummels you and sucks two of your friends away, making the battle pretty nasty. He loves to cast Ultima, doing around 7000 damage a pop, and if you last long enough for him to stick his grubby claws into the ground, prepare to have all your mp and hp sucked away like nothing. But your worries are over, and I've figured out how to beat him with little trouble. Unfortunately it calls for lots of mastered materia and it is STRONGLY suggested that Cloud be at level 99 or pretty close to it before trying to tackle this mother.
           Now lets start with our equipment. This is EXACTLY what you need to beat this guy. Equip Cloud with the Ultima Weapon (this you'll need solely for its status enhancements as well its 8 linked materia slots), the Mystile (there just isn't a sweeter armor that has a magic evade rate of about 60, giving you a 50/50 chance of dodging his repeatedly cast Ultima spells), and the Ribbon (this will nulify another of his attacks, which causes you to be confused, a major pain in the ass).  
            Here are the precious 14 pieces of materia you'll need. Start with Shield. This spell will save your ass be absorbing all elemental attacks as hp, and not let you lose any life (except Ultima of course, typeless damage). Master Magic is not needed, mainly because the only spell you'll be casting is shield. Final Attack Revive is the next installment, and your final attack better be mastered, cause you're gonna need all of its 5 revives to stay alive (keep in mind that there is a chance that you may not die at all, its all dependant on if you dodge Ultima or not.  Master Summon Mp Turbo come next, allowing you to repeatedly cast Knights of the Round, doing almost 130,000 damage a time. Add W-Summon to that and boost it to 260,000 a turn. You'll only have room for one Hp Plus and one Mp Plus so make sure they get you up to 9999 hp and 999 mp. Next, to help your dodging abilities, use 2 Luck Plus and 2 Speed Plus>. This will help you do what you need to do quickly as well. This puts up at 12. As for healing,  W-Item  will do just the trick, using elixers or an X-Potion and Turbo Ether. Lastly,   Mime, to let us repeatedly cast Knights of the Round without losing mp. 
            So how do you get it so Cloud is the only one to stay alive and not get sucked away? Thats easy, go into a normal battle and have him slaughter your team mates, so he is the only one alive. No strategy guide has thought of this. As soon as you start the battle Ruby will immediately stick his claws into the sand, avoiding lots of unwanted waiting and death. First thing you do is cast Shield on yourself, then as soon as your power bar refills, go to W-Summon and cast Knights of the Round, first targeting the claws, then targeting the bastard himself. From here on out, all you do is hit Mime everytime and prey you dodge Ultima. Keep it going, even if he sticks his claws in again, you can keep nailing him with mime, and it will still target his claws with mime. If you die, you will cast life2, and you'll probably have to use an elixer, but start the process over, casting shield then your doom combo.  Give it time and you will blast his ass to oblivion, and live the rest of your life knowing you have achieved an all time level of cool.
Thats it. Good Luck.