Final Fantasy III/Crystal Tower

Suggested team for this chapter:
 * Magus (later switch to Sage)
 * Black Belt (later switch to Ninja)
 * Summoner (later switch to Onion Knight)
 * Devout

In the NES version, the 3rd position is attacked more often, but the Black Belt has an armor that is even lighter than that of a magic user.

Forbidden Land Eureka
In an invisible passage on the 2nd floor you can find a chest containing a Ribbon. The chest is trapped and guarded by a Ninja.

A good strategy is to get quickly to the 8th level of Eureka ignoring the magic weapons. Down there you can heal and purchase Level 8 magic. On the 7th level you can battle Scylla for the best staff (in the NES version she also unlocks the Sage and Ninja jobs) and the Guardian for a featureless sword. Switch the Magus to Sage and the Summoner to Ninja, heal again and walk your way up collecting the other weapons: two more featureless swords and the Moonring Blade, probably the best weapon for the Ninja.

BOSS: Scylla & Co.
Amon is a bit of a challenge, but he is weak against physical attacks and poison spells.

The Kunoichi and the General can use no magic attacks, therefore they will be easy to beat.

Scylla and the Guardian are more of a challenge, because they can use powerful magic attacks that target all four Warriors of Light. Luckily, a healing fountain and a reviving fountain can be found just in next room.

Onion Knight equipment (NES)
The Crystal Tower is where you can find the Onion Equipment. All the five parts are dropped by Dragons.

In the NES version, dragons appear four times every 256 battles.
 * The first dragon appears after about 128 battles. If you already got the treasures of Eureka, that means: leave the Invincible, cross the Ancients' Maze, walk to the bottom of Eureka, then to the 7th floor of the Sylx Tower, back down to the 2nd floor and start climbing up again.
 * The second dragon appears after about 64 more battles, that is another visit to Eureka (buy tens of Shurikens) and back to the Sylx Tower.
 * The third and fourth dragon appear after about 10 more battles each.
 * Forty more battles and the cycle starts over, that is you need about 40+130 (=170) more battles to meet another dragon. Better go back to the Invincible, save game and reset the NES.

The dragons drop an Onion part only if they are hit by an instant-defeat spell. There are mainly six: You should better defeat the dragons on the second turn, or maybe a later one, for a better chance to get an Onion equipment part.
 * Black: Breakga, Death and Warp;
 * White: Mini, Toad and Exit;
 * Summon: Evoker's Bahamut and Summoner's Odin, but they have a higher chance to miss;
 * petrifying hits from Omnirod and Golem staff count as well;
 * items that cause instant defeat count, too: Black Musk, Black Hole and, if your level is 86 or more, Devil's Sigh.

The Dragons always drop an item when defeated; most of the times it will be an Elixir instead of an Onion part. The Thief can steal many Elixirs from them.

A frequently asked question: if the Thief steals one or more Elixirs from a dragon, does the chance of winning an Onion part get a boost? Unfortunately, this is not the case.

According to the analysis by Sir Bahamut, this is where each dragon can be met:

BOSS: Xande
Xande is a strong magician. Use now any Shining Curtain, then attack with any weapon and/or non-elemental spells.

You would think that Xande was the final enemy, but someone else appears: the Dark Cloud.

The Dark Cloud cannot be defeated now: it is part of the plot. Still, the Onion Knight can resist its attacks and make this scene tedious. To quicken up everything, remove the Onion Shield and make the Onion Knight attack himself.