Strategies that make the secret bosses look like jokes:

 

Sephiroth (Kingdom Hearts II): My own strategy: Spam Trinty Limit and use all the Reaction Commands. Be sure to dodge all his attacks. Just do this and he'll be finished quickly. You'll need to pack some Ethers too for when you run out of juice but I'm sure you can still do it without extra Ethers. It's safe to hit Sephiroth unlike these other bosses.

 

Mysterious Figure (Kingdom Hearts BBS): This guy makes Sephiroth look like a joke. We'll he's pretty easy and now I'm kicking his ass in a record time of just 2 minutes. Just load you deck with about 6 or 5 Thunder Surges. You should have 1 to 2 Fire Surges and two Curagas (Cura will work). You should really try and avoid all his attacks but I just charged him with Thunder Surge and he was defeated pretty quickly. When he does the clone thing, make sure to attack all the clones at once. If he's invisible and starts swinging his blades around like he's a maniac that means he's about to rage quit. Just use a lot of Curagas because his attacks do a lot of damage at this point. Thunder Surge his ass where you see his two blue blades. Spamming Thunder Surge is possibly the best and most easy strategy for beating MF. That thing with Aerosphere is difficult. Ventus: Easy Aqua: Mid-Easy Terra: You have to get lucky

 

Vanitas Sentiment (Kingdom Hearts BBS): Well he's pretty easy

Ventus: Load you deck with two Mine Squares and Two Tornados. This'll kill him in like what, a minute? Well this is the easiest way to defeat him with Ven.

Aqua: This is my own original strategy. Just load your deck with 6 Seeker Mines and 2 Curagas. The Seeker Mines do a lot of damage and they'll hit him even while in air. This is another eaasy strategy for beting Vanitas Sentiment.

Terra: With Terra it's much more hard, you have to use his final Finish Command with all the Meteors striking down. You have to do that and use Mine Squares. Don't bother hitting him, you should only hit him once or twice when the battle starts. That Finish Command with the Meteors is the key to defeating him.

 

Well these are the three most difficult secret bosses in Kingdom Hearts. I made this guide for anyone who is stuck on them.

These are secret bosses. No final bosses.

These are secret bosses. No final bosses.

 

*Not.

I couldn't get any of those to work. Being aggressive against MF only got me killed. I use Thunder Surge as a counter, hitting him after he misses me. The Sentiment's basically the same: dodge then strike.

 

And Sephiroth was nothing special. I just fight him like anyone else.

one more strategy for aqua , if you have some ice creams called :Fabracadabra which lets aqua get in spellweaver command style use 1 to get in the command style and one again to fully charge the command gauge and get the finisher which deals enormous damage to vanitas sentiment and grants you invincibility frames,also for all characters aerial slam is a great move so aerial slam and mines can help against vanitas sentiment because of the invincibility frames

 

and when he does the move where he stops and use a dark cannon , you can use ars solum and ars arcanum with terra and ven to deal some big damage(be carefull though not to get cought in front of the cannon)

 

Also for sephiroth in kh2 when he does the normal ground combo with the sword, guard then counterattack and do a combo but stop the combo before the explosion finisher,then sephiroth will not dissapear but he will flinch and after that he will use again the ground combo so repeat untill you deal big damage ,after some practice and learning his attacking pattern you can beat him without any problem,it just needs a lot of practice and i had to spend a lot of time to learn how to beat him but for others its pretty easy so give it a try

All you need to 2 tornado's, but if you need mine squares, you're a noob.