What a great start with a boss fight.

Check your Datalog to make sure that you have full intel on this guy (I got full intel without using Libra so your should be the same). Restart if you do not get full data.

Let's readjust our team again. Remove all equipment from Vanille and Snow, instead use the following set up:

• Lightning (leader): Sprint Shoes, Whistlewind Scarf, Growth Egg
• Fang (member): Sprint Shoes, Warrior's Wristband, Brawler's Wristband
• Hope (member): Eagletaon (weapon), Sprint Shoes, Sorcerer's Mark, Collector Catalog

Paradigms (Lightning/Fang/Hope):

• RAV/COM/RAV (default)
• MED/SAB/SYN
• MED/SEN/SYN
• RAV/COM/MED
• COM/COM/RAV

*** The reason I use Lightning as a leader for the last two chapters is because of her "Army of One" ability in combination with Whistlewind Scarf and Enkindler, she'll become a machine gun. You can spam the "Army of One" one after another to quickly stagger bosses as well as larger monsters very effectively and she cannot be interrupted during the skill animation which is really helpful. You'll see it in action to believe it. Make sure you take advantage of this newly acquired skill.

• BOSS (B-01): Anavatapta Warmech (x1)
  Strategy: This boss can either be pretty easy or super hard. That's because you start the battle with Odin and it is intended for you to kill it with Odin. Try mixing Odin's abilities (Stormblade, Lightning Strike, and Razor Gale) until it's staggered, once the Gestalt time near zero, use Zantetsuken to finish it off. Well, if you cannot kill it by now, the battle becomes really hard. I would suggest you "Retry" or do your best to kill it.

Check your Datalog to make sure that you have full intel on this guy (I got full intel without using Libra so your should be the same). Restart if you do not get full data.

When you are ready, save your game and continue. There are 2 treasures here in this area and it will not be accessible after you jump so make sure you pick them up.

• WEAPON (T-01): Lionheart (x1)
• ITEM (T-02): 9240 gil

The path from here is linear and can be accessible later after you beat the game, so I won't be listing enemies except something that worth mentioning. There is one scripted battle that won't be happening later that you ABSOLUTELY must get full intel. After you defeated 4 Adamantherons and walk further, a brief cutscene occur and you'll have to fight one Bulwarker and two Sanctum Seraphs, this is the one-time battle and has a hidden enemy "Targeting Beacon" which can only be summoned by the Sanctum Seraphs in this battle. What you should do is wait until the Targeting Beacons are summoned, then throw 1 Librascope for intel and finish them off.

Take an elevator at the end of the path. In the next section, pick up two items and fight a boss along the street.

• WEAPON (T-03): Rebel Heart (x1)
• WEAPON (T-04): Otshirvani (x1)
   
• BOSS (B-02): The Proudclad (x1)
  Strategy: 
  • This fight is pretty easy, you should be available to kill him in one stagger. 
  • Start with RAV/COM/RAV and immediately cast Libra.
  • When stagger meter is around 750%, switch to COM/COM/RAV.
  • RAV/COM/MED when you need healing.

At the beginning of the next section, you'll fight another scripted battle with a tortoise. My guess is you may have trouble dealing with it if it is your first time. First off, switch your paradigm to MED/SAB/SYN until 5 debuffs sticked on the turtle, then switch to RAV/COM/RAV, and MED/SEN/MED for healing. Debuffs play a huge part in battle against tortoises, so keep that in mind.

Let's move forward. There are 3 items in this area.

• WEAPON (T-05): Punisher (x1)
• ITEM (T-06): 15000 gil
• ITEM (T-07): Perfect Conductor (x5)

When you reach a gate, open it to the next section. There are total of 4 items in this area so you just have to follow the map.

• ACCESSORY (T-08): Blaze Rings (x1)
• ACCESSORY (T-09): Champion's Badge (x1)
• ITEM (T-10): Librascope (x1)
• ITEM (T-11): Particle Accelerator (x6)

At the end of the expressway is another gate. Good thing is from here, the path is linear. When you reach the first Save Point, go straight for an item:

• ITEM (T-12): Antares Deluxes (x1)

Backtrack and continue on the main path until you reach second Save Point. After the cutscene, you'll see a giant tortoise on the left side of the plaza, when you walk toward a few steps, it will start walking back and forth. Now you have two options, either you kill the tortoise or skip. If you don't kill the tortoise it will run into the building crashing the floor of the plaza and you lose 2 treasures. But since we are completionists, we'd want all treasures in the game, so kill the tortoise it is. Bad news is you'll die in one hit so you cannot fight same way you killed the previous one.

Let's setup a different strategy.

• This strategy requires you to have at least 3 TP so that you can summon an Eidolon, if you don't have, go kill some monsters. 
• Next, replace Lightning and set Vanille as the leader with her Malboro Wand.
• We only need 1 paradigm: Vanille/Fang/Hope as SAB/SAB/SYN

Now let's face the tortoise, Adamantoise:

• As soon as the battle starts, Vanille summons her Eidolon. This will paralyze the tortoise for a while.
• Take this opportunity to cast 5 debuffs on the turtle then spam her Death ability until it connects. 
• Retry if you fail until the tortoise is dead.

After you kill it, set your party back to previous setup.

• ITEM (T-13): Particle Accelerator (x6)
• ITEM (T-14): Plush Chocobo (x1)
• ITEM (T-15): Hellish Talon (x12)
• ITEM (T-16): Hellish Talon (x17)

Open the gate to the next section. This hallway doesn't have monsters and has only one item:

• WEAPON (T-17): Mistilteinn (x1)

Open another gate. Again, the path is straight forward and has 2 items.

• ACCESSORY (T-18): Power Glove (x1)
• ACCESSORY (T-19): Ethersol (x1)

Prepare a boss fight. Well, you fought it once, you shouldn't have any problem at all at this point. it may be a bit harder than the first encounter and the strategy is a bit different.

• BOSS (B-02): The Proudclad (x1)
  Strategy: 
  • Start with RAV/COM/RAV and hit as hit as hard as you can until it flies and when it does, it will heal itself to full HP.
  • Switch to SAB/MED/SYN until you sticked Deprotect and Deshell on it, then switch back to RAV/COM/RAV and COM/COM/RAV when staggered.
  • Heal if needed and repeat the process.

Save the game and descend to Edenhall.