Fenrir strat that I posted on my LS's forum today, and here it is for you. Not really looking for critiques, I'm only saying how I've been able to kill him. If some other strat works for you then that's awesome.
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Don't know why but here's a Fenrir strat that I've used ever since I hit 74 on Rng, and am 4-0 against fenrir for it. Though I die every time i fight him, the party wins and that's all that matters.
All melee and tanks must be 74+ with a /37nin for utsu Ni.
If a PLD is coming along in the fight make sure they are 74PLD/37NIN and another tank that has voke is going, i.e. 74war/37nin or a 70+ Nin main. However, if you have a tank that already has voke then you don't need a second tank. one of the key reasons DD must be 74 with /37nin
All other jobs must be 70+
Party Setup:
1)Tank1 -->Voking tank, 74war, 70+nin
2)DD --> A meleer that is crazy enough to take on tanking fenrir
3)WHM
4)Refresher --> RDM or BRD is good
5)Another DD, tank or mage --> 74war/37nin, 74pld/37nin, 74dd/37nin or another mage (blm, whm, rdm) is good for this position
6)Whatever --> literally whatever job and LVL can be put into this last position, another tank, more DD or mages....
Strategy (Before the fight):
1)Have the tanks, rdm, and bards make sword their main, and spirits within at the beginning of the fight. So they are going to need a 12 stack of sleeping potions and the opo-opo necklace. Pop all the potions before going in. DD that aren't going to spirts within only need to pop potions until 100% tp
2) if there is more than one mage that can cast haste, assign one to do so, both don't need to be the haste bi*ch.
3)buff up all the way, everything you've got except haste, eat food, whatever you do to prepare for uncapped BC battles.
4)enter the battle ground
Strategy (during the fight):
1) After the cutscene cast haste on the tanks, and DD
2) have the tanks and DD run for fenrir aggroing him whilst the mages keep their distance.
3) everyone who is going to "Spirits Within" and WS do so at the very beginning when aggroing fenrir.
4)main tank will then voke/war cry and any other hate getting devices to secure fenrir onto him.
5) after hate is secure, with mages always keeping a distance, fight as you normally would. 2 tanks makes it easy, 1 tank and 1 DD need to make sure they are pulling hate back and forth to help each other out in recasts of utsu and in case dispelga is used.
6) around 50% hp fenrir will 2hr, and the stregnth of his 2hr, depends on the moon phase and what day you fight him on. If there is a drk or blm in the party have him stun the 2hr, if their isn't have the whm run up and 2hr immediatly after fenrir's 2hr.
7) go all out, and fenrir dies.*
Things to watch out for:
Dispelga
Triple Bite
Things to note:
It is important that hate stay fixated on the tanks, blm's should stick to 2 spells (i.e. thunder 2, fire 2, etc.), and whm's stick to cure3's and cure 5's. the key to this strategy is to not pull hate.
Fenrir's 2hr can be stunned (blm's and drk's to the rescue), if the 2hr is stunned it makes the fight laughable.
Times to fight:
Easy fight: 0-20% moon cycle and lightsday
Normal fight: 21-69% moon cycle and anyday but darksday
Hard fight: 70-100% moon cycle and darksday
note* on #7: Being a RNG going all out for me is a bit different than other DD's, so if you don't have a rng as your DD, i honestly can't tell you the results of Whm --> Benediction and then not enough dmg to pull hate from the whm's 2hr.
If i'm so lucky and survive to complete the "going all out" step of the stragey it can go like this: slug shot > barrage > slug shot > eagle eye shot> icarus wing > slug shot. Depending how much HP fenrir has left he'll be dead after eagle eye shot. this however, is why i always die against fenrir. somewhere in that setup my blinks will have been spent, haste goes down, and heals aren't coming fast enough.
anywho that's what has worked for me.