Wow, how far in is that?
I cant beat the Dragon thingie at the end of the jungle...
If you're talking about the Elder Wyrm, he's not as hard as he is lengthy.
Just make sure you're calm, and have LOTS of pheonix downs. He regularly casts a spell which induces sap. Which SUCKS. The very first thing you need to do in the battle is get the Elder Wyrm with his two ent buddies and start off a mist chain, getting as high as possible. (It's easy to get higher Concurrences. I've managed to get Ark Blast numerous times with only two people. -- If you don't count the fact they have all of their mist attacks) This SHOULD take out the Ents (or was it trent? err... the WALKING TREE THINGS) and then focus on the Elder. You should have taken out a good bit of his health. Just switch out one character and start another chain. Continue to do this until all of your mist charges are used up. If you haven't killed him yet, you should at least have done MAJOR damage to him.
NOTE: Espers are useless in this battle, considering the only one you'll have (unless you power lvl'ed) is Bellias. The Elder Wyrm will focus on you no matter what, so you'll have sacraficed a needed character for a small ammount of damage.
Now just attack. This is all you can do at this point. Heal all status effects with remedy or their appropriate cures. (Antidotes, etc.) If you are inflicted with sap, NO BIG DEAL. Just pop a pheonix down on each person that dies, eventually curing the whole team. (Make sure one person is healing while the other revives). Now, if a whole lot of people die, this is what you do -
Have two people in Party (alive) and one dead person. Revive and Heal. If all but one is dead, pray you can use that pheonix down fast enough.
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That's about it.