"Oh my! It's Sephiroth! I better level up to level 100, get all the best equipments and a couple of elexirs (Sin Harvest is such an un-interruptible attack after all)! Then, I'll read a Sephiroth guide on Games FAQ's that tells me to not bother avoiding Sephiroth's attacks but just heal myself whenever I get hit! After all, my MP-recovering abilities will prevent me from ever running out of MP so I'll always be able to fully recover myself with Curaga! "
...
Ok, sorry. Let's just get to the point. I've never ever in my entire life seen an "advanced" Sephiroth guide that tells you about, for example, the "p0wnage-combos" that you can pull off on Sephy. For example, during Sephy's final phase, you can "combo Sephy to death" withou having him run/teleport away or anything to iterrupt the combo. Anyways... I'll explain all that later.
This is a guide that tells you how to beat Sephiroth at any time, at any level and with just about no preperation at all. You really don't even need to heal yourself even once.
Note: This is no newbie strategy guide. If you're about to fight Sephiroth for your very first time, it's not recomended that you use this guide.
Step 1: Preperation!
Make sure that you don't have any elexirs or other lame items. Then, just grab a keyblade with long reach and you're good to go!
Step 2: Enter the battle with Sephiroth!
This is a pretty tough part! First, you must walk up to Phil and select "Talk" in the command list. Press "X" to confirm, and Phil will ask you you if you know the rules. But instead of answearing "Yes, I know the rules" or "No, I don't", you will be forced to choose between a bunch of lame answears that doesn't make sense at all, like, for example "Pegasus Cup" and "Gold Match". The correct answear, however, is "Platinum Match", so pick that. Congratulations! You've just entered a battle with Sephiroth!
Step 3: p0wning Sephiroth!
Phase 1: This is Sephiroth's easiest phase and you should not have any trouble with it at all. Just do the old, basic jump approach and slice away until you reach the 2nd phase. Even my blind grandpa could make it trough this phase. If you seriously have trouble with this phase, you'll probably never make it through this battle alive. It's so easy and basic that you should be able to make it trough this phase without taking a singel hit. You can even do a p0wnage-combo (the same as the one used it phase 2, except it's much easier to pull off in this phase).
Phase 2: This is, usually, Sephiroth's hardest phase. However... if you manage to pull off a "p0wnage-combo", he won't even get a chanse to touch you. First, Sephiroth will jump to one of the corners of the battlefield and say "Come". Don't run after him. Run in the opposite direction to the opposite corner... and wait. Sephiroth will charge towards you, and then teleport... right in front of you! Oh no! Sin Harvest!!! No need to hurry. You should never get hit by Sin Harvest as long as you've got a faster responsetime than a dead beaver. Do a basic 4-hit combo, and he'll teleport-counter. This is where you'll be able to pull off the p0wnage-combo! Once Sephy teleport, activate the lock-on and roll towards the location where Sephy is about to show up. After a 4-hit combo, Sephy will always counter with a "jump forth, jump back sweep" out of his teleport. If you roll towards him right before he does this so-called "counter", he will miss... and when he "jumps back", he will be right in front of you... which means you'll be able to do another 4-hit combo! Obiviously, he will "counter" again, and all you need to do is repeat the process. If you successfully pull off a "p0wnage-combo", then Sephy should enter his 3th phase in no time and without ever getting a chanse to do his "Omnislash". If you screw up, however (p0wnage-combo requires good timing so it's not as easy and simple as it may sound), then you'll just have to avoid Sephiroth until he teleports. When he teleports, it's the same as the "counter", so just punish him with a new attempt on a shorter p0wnage-combo.
Phase 3: Sephy becomes invurnable and begins to glow. He will, once again, say "come" and then teleport away. But this time, you will be surrounded by a ring of glowing balls. Just jump away to avoid getting hit by them. Sephy teleports to the center of the battlefield and summons a swarm of meteors. Just make sure that you're close to the "walls", as far away from Sephy as possible and jump>glide as soon as the first meteor hits the ground. Once all the meteors has hit the ground, stop gliding and start avoiding the meteors as they begin to move around. This phase is usually pretty easy, but don't let your guard down and don't relax just because it's easy, or you may end up screwing up just because of that (watch video below). After a while, the meteors will explode and a big, glowing meteor thingy will be sent your way. Super Glide to dodge it, but make sure you do it SERIOUSLY, and DON'T screw up by gliding straight into the invisible walls just because you feel this part is too "easy".
Phase 4: Time for the "death-combo"! After the meteor phase, just make sure to dodge Sephiroth's new attacks and hit him with a 4-hit combo. A good way to do this is to roll away just as Sephiroth does his "dark whirl" and then quickly run towards him before he land and hit him with the 4-hit combo just as he land. The "death-combo" shouldn't be any hard to perform, because it's a lot more simple than the p0wnage-combo. As soon as you've hit Sephy with a 4-hit combo, roll away. Don't bother with the lock-on, just roll away. Sephy will counter with dark whirl, and he will counter faster than he did before. However... dark whirl has so much lag time that you'll be able to run back and hit him with another combo. Just repeat until he dies. It's really that simple.
And now, here's a video of me beating Sephiroth on level 71 on expert: ShadsVSephy
An important thing to notice is that if you don't time the "p0wnage-combo" correctly, Sephy might not be stunned, or in the middle of a new move. If this happens, you may either just attack him again, or roll away depending on the situation. This is shown in the video during the first phase of the battle.
During the second phase, I miss the first teleport-counter... but I p0wnage-combo the rest of Sephy's HP all the way to the 3th phase.
During the 3th phase, I'm playing far too relaxed. I was orginally planning on not getting hit even once trough the entire battle, but because of my self-confidence, I got hit once. Oh well... such is life. I'll make another "no dammage" video another day. I don't have a video camera, but my friend who lives about 7 miles away does. When he visited me and we recorded this video, he couldn't stay for long though, so I didn't get the time to make another video where I beated Sephy without doing any stupid misstakes. But the next time he visits and brings his video camera, I'll do a new "no dammage" video. And in a way, I actually find it funny that I took dammage from once of those things that most people don't have any trouble with.
4th phase is just death-combo... except the fact that I don't finnish the death-combo. I felt like finnishing the battle in a weird and unusual way, so I used "Sonic Blade" instead. I had to use Sonic Blade twice, though since the first didn't hit enough times, but that only makes it more exciting.
Edit: No-Dammage Video: http://www.youtube.com/watch?v=ClCVw53FCZk
That's all, have a nice day.