In general, there are too many enemies with high Attack. It's best to leave the easiest enemies for last and defeat all the others first.
Enemies to watch out for include:
Other enemies are still dangerous, but the enemies listed about require particular caution.
@Party's final boss. Well, there are still plenty of bosses in @Party II that are stronger than Satan…
The Stone-type monsters that had been present in every location since Dragonsdale are now gone - instead, EvilThunders have appeared.
Both have high HP and occasionally heal themselves with Meditation, so the strategy of slowing chipping away at their health is not very effective.
EvilThunderA excels at disrupting tension and inflicting abnormal statuses.
If you get hit with Seal, SandmansArrow, or Kafizzle, you essentially need to recover and it becomes that much more difficult.
The worst is Oomph, which increases Satan's Attack level; it makes the battle impossible unless you neutralize it somehow.
It also attacks fairly often, so even if EvilThunderA only has its Attack buffed, it's still tough. It's recommended to neutralize this as well.
EvilThunderB has a wealth of area-of-effect attacks, including Bahamut, Scorch, and Kazapple.
While EvilThunderA is higher priority to defeat, EvilThunderB often often uses Golem and Carbuncle for defense, so you may have to wait to attack with your carefully built-up tension.
It can also suddenly cast Whack, so be especially carefully when soloing.
TL note: Portions of the following advice are irrelevant/incorrect.
In the original Japanese code, Satan was one of several enemies in the game that were seemingly set to the wrong jobs (Soldier/FallenAngel instead of FallenAngel/DarkKnight - the former is what it was set to; the latter is what was written in the code comments). These have been corrected in the English-translated version, meaning that portions of the following advice taken from the Japanese strategy guide are incorrect.
Satan is quite powerful in both physical and magical attacks.
The most dangerous is Omnislash. If you have few party members, it can cause significant damage, so immediate recovery or prior physical countermeasures are necessary.
In solo play, Satan's Attack level is lower due to the party size penalty, so even just increasing your defense can be quite effective and is worth considering
Beyond the above, the high probability of single-hit attacks like Meteorain and CrossSlash means that the average damage-per-turn tends to be quite high.
It's moderately difficult, but if you can successfully stall for time, the attack reduction from Meteorain eliminates the threat of physical attacks.
If you're confident in your defensive capabilities, it might be worth trying.
On the magic side of things, it uses Bioga and AngelOfDarkness to moderately disrupt attacks, while ShadowFlare and HeartlessAngel - which counter physical defenses - can lead to trouble.
If you can block these with magic countermeasures, you'll be able to act, which makes things more stable; but since physical attacks are the source of damage, it's not always that simple.
Regarding the order of dealing with these enemies, there's also the strategy of defeating Satan first.
The tension disruption isn't as severe as it was with Black Citadel's bosses, and Satan's Attack level is outstanding, so the idea is to eliminate him while he has had few turns to act.
Conversely, if you can recover quickly from high damage, an effective strategy is to eliminate the EvilThunders first, as they are the source of accidental deaths.