The Necromancer can get about half of his Dark Arts spells without needing to beat the game and enter the Sealed Temple. From one of the FF5 Advance FAQs on Gamefaqs:
Da
rk arts:
=======
Drain touch, learned automatically from mind flare.
Dark haze, learned from the exoray flower (sealed temple)
Deep freeze, learned from Assassin (sealed temple)
Evil mist, learned from Dragon zombie (drakenvale)
Meltdown, learned from Liquid flame (Phoenix tower-wall boss)
Hell wind, learned from object d'art (Bal castle basement)
Chaos drive, learned from mini satin (Sealed temple)
Curse, learned from Ironclad (Sealed temple-enuo's domain)
Dark flare, learned from X-deaths ghost (Kuza castle)
Doomsday, learned from Hades (Sealed temple-enuo's domain)
That should give you enough to work with, as all of those spells are really strong. You'd have Evil Mist (poison) and Hell Wind (wind) halfway through the second world, both of which strike for more damage than Fire 3. Plus, the Necromancer can use the "Oath" summon command to get through world 1/2 before those spells start appearing. In other words, it wouldn't have to be a pure Rod-breaking exercise. The lack of healing outside of Flame Rod/Flame Ring use would of course be a real issue...
The Oracle's stuff is not purely random. I'll just cut and paste from the updated FF5 Advance Algorithms guide:
*******************
9.1) Predict Spells
*******************
Spell is decided by last digit of caster's MP value.
MP Spell Element Status Effects Abv.
0 Cleansing CS
1 Deluge Water Toad DL
2 Eruption Fire HP Leak ER
3 Starfall Death Damagex2 SF
4 Rockslide Earth Damagex2 RS
5 Divine Judgement Holy MP damage(2nd)+Recovery DJ
6 Healing Wind Holy Dispel Recovery HW
7 Blessing Holy Regen Recovery BL
8 Hurricane Wind Silence HC
9 Pestilence Poison Poison PL
***************************
9.2) Predict Damage Formula
***************************
Predict damage formula:
Attack = Base Attack + (0..(Base Attack/8))
M = see below
Damage = (Att - Mag Def)*M
M is decided by last digit of target HP value when a prediction is being made.
E = Enemy, P = Player
Abv. Att 0 1 2 3 4 5 6 7 8 9 HP Last Digit
CS(E) 250 3 6 9 12 15 18 21 24 27 30 = M
DL(E) 180 2 5 8 10 13 16 18 21 24 27
DL(P) 180 1 1 1 1 1 1 2 2 2 3
ER(E) 165 2 4 7 9 12 14 16 19 21 24
ER(P) 165 1 1 1 2 3 3 4 4 5 6
SF(E) 190 2 5 8 10 13 16 18 21 24 27
SF(P) 190 1 1 1 1 1 1 2 2 2 3
RS(E) 160 1 3 4 6 7 9 10 12 13 15
RS(P) 160 1 3 4 6 7 9 10 12 13 15
DJ(E) 220 3 6 9 12 15 18 21 24 27 30
DJ(P) 240 10 10 10 10 10 10 10 10 10 10
HW(P) 155 3 6 9 12 15 18 21 24 27 30
BL(P) 210 3 6 9 12 15 18 21 24 27 30
HC(E) 200 2 4 7 9 12 14 16 19 21 24
HC(P) 200 1 1 1 2 3 3 4 4 5 6
PL(P) 180 3 6 9 12 15 18 21 24 27 30
You need to know the last digit of your MP and the last digit of the target's HP. Should make for some fun micro.
You know, we could even do some of these classes succession game style, passing the save file back and forth. Someone does Karlabos, someone does Byblos, etc. Might even be fun for people to follow in the forums.