== Lunar Subterrane - B12 ==
Before you take another step, make sure you are equipped properly and have the
proper Abilities on your team. If you've been following this guide, Kain should
have Jump, Focus, Darkness, Phoenix and Cry in his Auto-Battle slot. Rydia
should have Black Magic, Summon, Fast Talker, Piercing Magic and Bluff in her
Auto-Battle. Cecil should have Attack, White Magic, Brace, HP +50% and any
ability in Auto-Battle. Rosa should have Aim, Dualcast, MP +50%, Omnicasting
and Pray in her Auto-Battle. Edge should have Attack, Throw, Steal, any ability
and Bless in his Auto-Battle.

Watch the scenes that ensue. You'll receive the CRYSTAL from Golbez and the
final battle will begin.

Only Cecil can use the Crystal. Don't bother buffing anyone since Zeromus'
initial attack will remove them. However, you can hit Darkness on Kain and make
sure he has a round or two of Focus. Also, make sure everyone's ATB bar is full
so they can act immediately. Use the Crystal to face:

    O--------------------------------------------------O
    | #197 - Zeromus                                   |
    O---------------------O----------------------------O
    |  Level ........ 68  |  Weakness                  |
    |  HP ....... 150000  |    None                    |
    |  EXP ........... 0  |                            |
    |  Gil ........... 0  |  Resistance                |
    |                     |    None                    |
    |                     |                            |
    |  Steal              |  Absorb                    |
    |   Dark Matter       |    None                    |
    |                     |                            |
    |  Drops              |                            |
    |   None              |                            |
    |                     |                            |
    O---------------------O----------------------------O

Zeromus has a few attacks, the most brutal being Big Bang and Black Hole. Big
Bang will cause massive damage to everyone and leaves them with Sap. Luckily,
you have a forewarning on this because Zeromus will shake before he uses Big
Bang. You should have everyone Defend or Brace at that point and have Rosa on
standby for quick healing.

Black Hole will remove all your hard-earned buffs and remove any negative
status effects from Zeromus (like Slow). One upside is that it also removes the
Sap status that Big Bang causes.

Zeromus also uses Osmose, Flare and Whirl (a Tornado-type attack that hits the
whole team). He will also use Counter:Flare to any Black Magic attack. He uses
Counter:Osmose to Summons.

Zeromus has three major attack patterns. When his HP is anywhere between 90000
and 150000, his attack pattern will be:

Black Hole -> Big Bang -> Black Hole -> Osmose -> Big Bang (x2) -> Osmose ->
 repeat from start

When his HP is between 30000 and 89999, the attack pattern will be:

Osmose -> Big Bang -> Black Hole -> Flare -> Osmose -> Black Hole -> Big Bang
 -> repeat from start

When his HP dips anywhere below 30000, the attack pattern will get much worse:

Meteor -> Osmose -> Whirl

Here's a small list of what each character will do throughout this battle.

Kain - Jump. Don't even bother with Focus (but maybe hit Darkness on him). You
  may want to keep him on the ground if he needs healing. Also, if he has Sap
  on him, you might want to have him get hit with Black Hole to remove it.

Rydia - Summon Bahamut. Yeah, yeah, Osmose is a pain in the ass but that's why
  you have Elixirs along. You DID remember to buy a ton of them, right?

Cecil - Attack. Or help build defenses.

Rosa - Curaja and Blink/Protect/Shell/Haste. Hopefully you have Dualcast on
  her. If not, then you'll have to do it once every round.

A certain degree of common sense should take place here. If you need to use a
Dry Ether, Elixir or Megalixer, USE IT! Don't worry about whose turn it is,
just use items as you need.