A wench from Whitecap in Balfonheim hires you for the job. She's haunted by dreams with demonic horse. She asks you to take care of the source of these dreams. To do so go to Pharos.
About 276 000 HP
Resistant to Libra,
Vulnerable to Holy,
Ixion can be found in "basement" under Pharos. Teleport there, approach the Dais of Ascendance and use it to get to Penumbra. Don't move - hordes of Abaddons, Bull Abaddons and Mistmares will attack you. Kill them all till they stop appearing. Get back upstairs, touch the crystal to replenish your HP and MP and go back to Penumbra. If you can't see him run around the shaft and when you reach the elevator the Ixion should appear.
It's important to set "Ally: HP<60% ---> Curaja" for everyone and "Ally: any ---> Esunaga" for at least two characters. Don't forget also to set "Self: MP<10% ---> Charge", because Ixion is immune to Syphon. Also equip Bowline Sash on one of the characters with Esunaga set in gambits.
Attacks of this demonic horse are (except for the standard one) Curse causing on everyone in range Confuse, Disease, Poison, Sap and Fearga draining a great amount of MP from every hero in range. Additionally at the end of the fight his defense raises.
The most annoying thing about Ixion is his combination of few Dispels in a row and then Fearga leaving you without buffs and MP (or the other way around: Fearga and just after that few dispels in a row). The most important thing is to have mana to heal your party, the buffs aren't so important.
Bounty: 3000 gil, Sapping Bolts, Ragnarok