Bravely Default Nemesis Strategy: Belphegor

Belphegor is a rather interesting nemesis to fight, who cycles its elemental weakness every time you exploit that elemental weakness.  This is for the level 20 version of Belphegor, higher level versions will obviously take longer.

Recommended party:

• Three Black Mages and one White Mage.
• The Black Mages should be at least Job Level 7, so they can cast the level 3 black magic spells: Fira, Blizzara, and Thundara.
• The White Mage should be at least Job Level 6, so they can cast the level 3 white magic spells, most notably Cura.
• The White Mage should also have black magic at Job Level 8, so they can take the Black Resonance support ability.
• Job Commands on the Black Mages should be Miscellany, so you can Examine.
• Your White Mage will be healing pretty much every turn, so their Job Command doesn't matter much here.
• For support abilities, you'll want Abate Fire on everyone, and Black Resonance on your White Mage.
• Above level 20.  Due to the grinding I did to level people up in black magic, my party is level 30.
• Equipment that amplifies the elemental spells.  Rod of Fire, Lambent Hat, etc.

Special Moves:

• You shouldn't really need these here if your black magic is decent enough.

Strategy:

• Right away, Examine Belphegor and Default on everyone else.  Take a look at its weakness, this will cycle throughout the fight in the order Lightning → Fire → Water → repeat.  You can't go at this blind, you must Examine and know what to cast at all times.  Belphegor will be healed by anything that isn't what it's currently weak to, including physical damage.  If you have multiples or get another one later, though, its weakness will already be revealed and you can skip this step.
• On turn two, hit Belphegor once with whatever he's weak to, default with your other two Black Mages, and heal the party with your White Mage.
• On turn three, default on your first Black Mage.  Your second Black Mage should be at 2 BP, so brave twice and cast the entire elemental sequence.  Heal the party with your White Mage.
• On turn four, default on the first two Black Mages.  Your third Black Mage should be at 3 BP, so brave three times and cast the entire elemental sequence, plus the next spell in the sequence.  Heal the party with your White Mage.
• Belphegor should die on this turn.  Yeah, you could do it faster by using lots of brave everywhere, but I ran out of Belphegors to fight before I could try that.
• If you take too long, Belphegor will summon three spheres.  These spheres do the same weakness cycling thing that Belphegor does, in the same pattern, but their weaknesses will be randomized.  Examine all three in one turn, then on your next turn, cycle the weaknesses of everything so that Belphegor and the Spheres all have the same weakness.  Once the weaknesses are synchronized, resume casting the elemental sequence.

For higher level versions of Belphegor:

• Your White Mage should be wielding a staff and have Rejuvenation ready to go (go trigger random battles and heal 10 times) with the best HP/MP recovery level 5 and BP boost level 2.  I typically have Cure K.O. on Rejuvenation as well, just because it makes the most sense.  This is also the ability I've sent.
• Pop Rejuvenation on the second turn and then again as soon as it comes up every time it comes up.
• Your White Mage should still heal every turn.  This is important to keep being able to cast Rejuvenation.  If you don't really need the heal, cast Cure or something.  Work on shielding/protecting allies, I dunno.
• If you feel ballsy enough to hold out for Lux, do so, assuming you've got it at +5 turns.  The rest of the parts on Lux don't really matter.
• This strategy is scalable to the higher level versions of Belphegor.  After the first two turns, you'll always have a Black Mage who can brave twice and cast the entire sequence.  It also grabs you an extra turn on your White Mage that it doesn't even use.  For higher level versions, you'll want to work a bit more at getting your White Mage's BP up to 3.

I hope this helps anyone else out there who wants to try this fight.  I think I'll make a series of these posts as I figure out strategies for each of the Nemeses.  Up next will be Leviathan.