How to beat "The Impure Cuchulainn" Esper in the Garamsythe Waterway in Rabanastre?

I have maxed out stats on all my characters and I still end up having all my characters die. That constant Sap environment that never ceases is just killing me and the fact that the Esper has high HP and those annoying minions he constantly summons doesn't help either. I end up spending most of my time healing and restoring fallen characters than I do whittling down the boss's health. Also dispatching the minions are a bit distracting too. Does anyone know a way to beat it or maybe some armor/accessory/item I overlooked?

Well, first of all magic isnt the way to go on beating him..as all magics are halved, so only use cure spells and effect spells to help you out..make sure to cast dispel as soon as the battle starts to take away his stat effects...he has 126165 hp, so he should be a bit of a chalenge..but first of all i think you should wqork on your battleing skills as i hav beaten him and my guys arnt close to being maxed there average is level 40+ so work on that first, then once he starts summoning just use firaga to wipe them all out simple..keep one char out (fran most likely) to heal and to keep out of range..equip one char with black belt to block against dispel from him and esuna gambit on everyone..hope this helps if you still cant beat him post again and tell what part you are dieing at like how close do you get to killing him and then i may be able to help you a bit more

Hahahaha... i used to have this problem like u, so i think a little help should be okay.
First of all... what level are you now? I suggest that you fight this Esper at level 50 or above that. Have the leader equipt with small range weapon (your best 1H or 2H sword...or an axe, katana... whatever that is to your convinience) and also get him a bubble belt to double his HP. For this character, first gambit should be ally=any, phoenix down or rise; second gambit is foe=strongest, attack. (third gambit and so-on is up to you).
For the second character... equipment is same like the leader. Set first gambit to be ally=HP<60% x potion or cura (curaja would be better if you have it). Second gambit to be foe=weakest, attack (to get that annoying slime). Third gambit is foe=party leader target, attack.
Third character is best with long ranged weapon (such as bow or gun), equipt also with black belt (so at least there still one character remain to immune when Cuchulainn cast Disable). First gambit is ally=any, remedy or esuna. Second gambit is foe=party leader target, attack.
Notes that before entering this fight, beter have level 3 remedy so that your remedy can cure multiple bad status such as SAP, disable, poison... etc. Also... cast all of your supporting magics such as shell, protect, and regen. try to re-casting them when the effect wears off during battle.

i used basch as my primary attacker,balthier as my bak-up crew,and vaan as my in between(where he is attack half the time and supporting the other time)it be really easy with the zodiac spear,because when you have berserk,haste,and bravery on,you do 9999 damage very quickly,making this fight very easy.bubble is very important for all esper fights that are not storylined and curaja can help out ALOT,as cura would be too weak and curaga would heal one at a time.renewing morions or ring of renewal can help mantain your hp also.

Ahh....... I remember this esper all to well. I was lvl 60 when I went after him. My party consisted of Fran, Basch, and Ashe. I didn't really have a strategy when I fought him, I just knocked the life out of him and healed when needed. It was hard and I had to cast Arise often, but he eventually went down. Also I found that the Turtleshell Choker works wonders against espers and hunts that have a lot of hp and you need lots of mp for healing, just make sure you don't need you gil immediately because the choker uses gil for spells instead of mp.

I was below 50 with all my characters when I beat cuchulainn. He's not even that hard.

I was completely unprepared when I found him. I had no good spells except for arise, I didn't even have bubble, lol. My only healing spell was curaga. And my weapons were pathetic, basch had defender, ashe had either masamune or muramasa, and fran had only the holy lance. My weapons were horrible for that fight.

and did you win,because it not only counts for weapons but armour,as armour is a life saver(not the candy)

I won....... barely, all 3 of my characters were in critical except for ashe, she was dead, lol. Also I only ever used 1 gambit back then, Foe nearest visible- Attack. I never used strategy back then.

the gambit hp-lowest hp-atk is more useful because you atk the one with lowest hp and the other one's put party leader target,so you can gang up on the weakest one.

I learned that not to long ago, lol.

with the right stuff,you can beat anything(and when i say that,i mean the guide book to you is god when you have this game.)

I agree, lol. Unfortunately, I got it after I killed Yiazmat.

so that book,in basic terms,was useless unless you needed to do sidequests,espers,and/or find weapons?

Dude I only had diamond swords!

shoulden't diamond swords cost more because there made of diamonds?

uasaly you would think thats the case but you have to remember that this is Final Fantasy things are different then they would be here.

i mean come on,who would want to buy a stonebow,look at the thing!!!i wonder how fran could have carried that thing ...

Wonder how penelo could use it?

I beat this guy at level 43. He wasnt that hard. Either your characters arent developed that well or you are trying to beat him to early. The sap thing isnt that bad, just keep an eye on your health and heal when your HP gets just below half.

Heres what you can do:

First make sure everyone has Haste/Bubble if you want Protect/Shell can also be used. Equip Black Belts to counter Disable. Cast Berserk on your main attacker. Constantly Heal with one character. Then Attack, heal, and support with your final Character. Also dont forget to cast Dispel on him as well.

Do that and you will win, That is basically that strategy for every boss, and they go down easy. Equipping a Katana and Genji Gloves on your heavy attack while they have Berserk/Haste equals you owning the boss.