Requiem of Sin

This is not an easy battle. It is basically an uncapped version of the Chains of Promathia mission Head Wind. Like the mission, the chances of sleeping the Shikaree Trackers is slim to nil, leaving your best bet to open with an Elemental Seal Sleepga to buy a little time. Past that, it is of extreme importance that a BLM or RDM comes along whose sole purpose is keeping the Rabbit bound (it won't sleep) and the Wyvern asleep. The Wyvern is particularly annoying, as it can do Healing Breath III for 900-1000 HP on whatever it is you're killing. And believe me, 1000 HP goes a long way in this fight.

The kill order is Z -> Y -> X -> Z's Wyvern -> X's Rabbit. Z is a PLD/DRG and seems to start the fight with Invincible auto-popped. Wait for it to wear and then unleash your best attacks. Z needs to die as soon as possible to succeed. If your party is going to wipe, it needs to defeat Z beforehand. Once Z is down, ignore her Wyvern (the RDM should keep it asleep as possible), and move on to Y. When Y is down, move onto X. As each Shikaree goes down, the battle becomes incredibly easier. The highest odds of wiping come while killing Z - if you do indeed wipe after Z is defeated, make sure to wipe AWAY from the pit where the Shikaree spawn. If you do this, you can safely RR with plenty of time (it's a 30 minute BCNM). However, it is paramount to remember that the Wyvern will NOT retreat to it's spawn point, so make sure wherever you wipe, you don't bring Z's Wyvern with you.

Bear in mind that Y will use Blood Weapon and X will use Familiar as their 2-hour abilities. Familiar isn't particuarly intimidating, however, Y's Blood Weapon can be rather damaging if she gets a few clean hits off. Binding her, Stunning her, or finding some method of cutting down her attacks while her 2-hour is up is certainly recommended.

Also, like Head Wind, the Trackers have a permanent Auto-Meditate effect, and they will SC on your tank. Although you can split them apart, they will return to a shared hate system when they perform skillchains. The Blackened Muddy Siredon item from Head Wind will also work here, temporarily halting their TP gain, but the mission is certainly winnable without.

In short, Z -> Y -> X -> Pets. Keep the Rabbit bound and the Wyvern asleep. Elemental Seal Sleepga to open and use that small window of time to zerg Z into oblivion, then move onto Y, and then X. If you wipe, wipe away from their starting point. Keep your cool and bring your evasion gear, this is a good BC for it.