Setup:
Cloud Equip: Masamune, Escort Guard, Curse Ring (As much Strength as possible, Gigas Armlet not viable due to lack of 6 Linked Materia slots).
Cloud Weapon Materia: Mime + Double Cut, Barrier + All, Revive + All
Cloud Armour Materia: Hades + Added Effect, Mystify + Added Effect, Destruct + Added Effect
Aeris Equip: Princess Guard, Minerva Band, Choco Feather (Princess Guard + Slash-All puts Shield on the entire team after "Deployment").
Aeris Weapon Materia Equip: Revive + All, Restore + All, Heal + All, W-Magic + Slash-All (1 Star)
Aeris Armour Materia Equip: Phoenix + Elemental, Gil PLUS + Gil PLUS, HP Plus + Gravity
Tifa Equip: Master Fist, Shinra Alpha, **** I forgot to equip an Accessory after giving Cloud the Curse Ring. I'm an idiot.
Tifa Weapon Materia Equip: Leviathan + Elemental, Double Cut + Enemy Skill, Counter Attack + Counter Attack
Tifa Armour Materia Equip: Transform + Added Effect, Mystify + Added Effect, Counter Attack + Counter Attack, Counter Attack + Counter Attack
Items used:
Yellow Waves
Hero Drink II
Soft
Elixirs
Megalixirs
Graviballs
T/S Bombs
Lucky Pills
Make sure you start the fight with Tifa in the Front Row and an empty Limit Bar (So she can do 4x Cut without trouble) and make sure Cloud has a full L4 Limit Bar (This will be vital). The first part is pray that Magitek Corruptor doesn't hit Aeris and get the following setup as quickly as possible: 2 Yellow Waves on Netzechariah, Dragon Force on Tifa, Hero Drink II (After Dragon Force), Wall (Cast on Party).
At the start of the fight Netzech tends to follow this pattern: Magitek Corrupter, Magitek Ray x3 (1 per party member), Magitek Bomb x2 (Hits all targets), Magitek Shoot x3 (1 per party member), Tank Purge (DeBarrier effect). Then he will do nothing until 13 actions (not including Counter Attacks) have been used against him at which point he will use Deployment and phase 2 of the fight will begin.
If you got Dragon Force/Hero Drink II/Yellow Waves set up properly then Tifa should do several Critical Hits on the boss for heavy damage and also counter for heavy damage whenever hit by various moves. Keep the party alive any way you can but be careful not to let Tifa get Petrified and use a Soft on her ONLY when the timer above her head starts to get low so you can make use of the extra damage of having Slow-Numb with the Master Fist.
Once Netzechariah stops attacking during the first phase (the period before he's allowed to use Deployment) Tifa can then proceed to hit Netzechariah with 4x Cut and the Master Fist bonuses for some hefty (barely adequate) damage. Once Netzechariah uses Deployment have Cloud use Wall, Aeris use Slash-All on the party to grant Shield to everyone and stop using 4x Cut with Tifa.
With Deployment, Magitek Bit and Byte enter the fray and they need to be dealt with, this is done by having Tifa use Graviballs and T/S Bombs on Magitek Bit and Byte, Aeris using W-Magic with Demi and Demi2 and Cloud Miming Aeris's W-Magic since they take normal damage from Gravity attacks.
Now that you've used Shield on the party you'll now absorb a good chunk of Netzechariah's elemental attacks. This has several benefits because absorbing Tidal Wave will actually DeSpell Tifa's Death Sentence from Hero Drink II and also cure her Silence, this allowed her to use Laser to finish off the Magitek Bit/Byte when Demi2 stops doing 9999 and absorbing Geocrush will actually grant Recovery to whoever it targets instead of K.O. Just make sure to heal up when hit by Magitek Ray/Bomb/Shoot from Magitek Bit/Byte when they happen.
Either way once Magitek Bit/Byte are down, Netzechariah should have finished his attack pattern and you'll have some breathing room. You should also at this point have 26 Attacks to finish off the remainder of his health. After 13 Attacks he'll Ascend (Be unreachable for standard Melee attacks) and use Overclock which grants him Haste (This is a trap to get you to waste a turn DeSpelling it) and 13 Turns after that he'll use Mammon Machine and tear your party to shreds.
With 26 Attacks to go you'll need to put out some heavy damage per attack and this is where that Full L4 Limit Bar Cloud has comes in. I forgot that Masamune gives 100% Critical Chance so I gave a Lucky Pill to Cloud (The Auto-Critical hits of Omnislash can still go Critical and deal x2 Damage, unless this got changed or something). Since you used 2 Yellow Waves at the start of the fight Netzechariah should have no defence at this point, now you'll want to use Omnislash and MIME THE EVERLOVING **** OUT OF IT.
With Escort Guard and Curse Ring Cloud has 80 Strength and the +100 Attack of Masamune gives Cloud 180 Attack Power. Even with Yellow Waves I was only doing ~1600-~1700 per hit or rather ~25000 per Limit Break. This means that with the point where Magitek Bit/Byte died I needed Netzechariah to have less than 650,000 HP (26 x 25000 HP) and fortunately thanks to the 4x Cut + Master Fist antics of Tifa along with Counter Attacks at the start he had around 596000 HP when he used Deployment. Meaning I was able to constantly Mime Omnislash and have about 2 turns to spare when he finally dropped.
