can any one tell me how to beat this stupid bitchs 3rd stage
i get to her and the cast mega death or wot ever its called
she shits me to tears!!!

Ok well, when she is in her second form she will cast zombie on your characters. Dont remove the zombie effect. When you get to her third form, Mega Death will be useless against characters with Zombie. Good Luck!

If you have Deathproof/Death Ward abilities they would help you a lot, trust me. If you haven't had them before Yunalesca, then just stick to Joeshie's advice.

stay in zombie form during the third round, some of her attacks will heal you. then have yuna grand summon her arse

Yunalesca will also cast Hell Biter in her 3rd form. As long as at least one character is in zombie status, you'll be alright.

Just equip sensor to one of your three character's weapons and, once Yunalesca's 2nd form HP is getting low (if you're like me, you can pretty much know down to the dot how many more turns of what will finish her) have Yuna rip out Bahamut or something. Why? Because Summon's are immune to status problems like "Instant-Death." You can then proceed to let Bahamut fight it out until he dies or you can immediately dismiss him.

Another way is to pray. No, I don't mean the ability pray, I mean you, the player, actually get down on your knees and pray that you're lucky (and not the FF type of "luck"!) because sometimes Yunalesca's Mega Death misses.

Or yeah, "Deathward" and the like are helpful.

Or stay in Zombie Status.

And, of course, it ALWAYS helps to start the battle off with Hastega. THE MOST USEFUL SPELL OF THEM ALL!

- PTM