Final Fantasy IV/Lunar Subterranean

This walkthrough will explain only the basics of the underground as well as how to get the major weapons and armor in the level. There are many chests along the way that contain useful items, but this walkthrough will not describe each one.

Passage in Lunar Hideout
Go through the Lunar Path once again, following it as before until you reach the Lunar Lair. This time, go behind the platform where you met FuSoYa, to the door in the back. In this crystal room, there is a tile in the center; stand on the tile and you will be transported to the Lunar Subterranean.

Murasame
When you reach the underground, go immediately to the left and through a hidden path in the wall. On the other side is a staircase. Go down these stairs. Continue forward on the path, and you will go down 3 sets of staircases, eventually reaching the podium where the Murasame sword is resting. You will have to fight the White Dragon (Pale Dim) to get this sword. He has basic attacks that damage the whole party, using the Slow spell as a counter. He also counters summon magic with earthquakes, so be sure to cast Float before the battle to protect the party if you plan on summoning. When you defeat the enemy, you can equip Edge with this powerful sword. Return to the entrance of the underground.

Passage
Head down from the entrance, and go through the door. In the next room, go east to find a hidden path in the wall. Go north, collecting the chests along the way, if you like. Continue north along the hidden path, and you will eventually reach another door in the northwest corner. Pick up the chest containing a Dragon Shield continue through the door. In the next room, head down from where you enter, and take the first door you reach.

Staircases
This next room is large, with several levels. From the entrance, head east taking the first staircase south. On the next level, go all the way to the right and down the staircase. Finally, go to the left and into the first door you reach. In this room head all the way west and into the only door you see. The chest here contains a Stardust Rod and also a tough battle with a Behemoth (he counters everything you throw at him, so be careful). Finally, go toward the southeast of this room, to go on to the next section.

Continuing to the Core
In the next room, go down the staircase, a battle with a Blue and Red Dragon and a Crystal Shield are in the chest directly outside the door. In the next room go north then east, through the invisible paths in the wall, picking up a Protect Ring along the way. Take the door to the south first to collect a Crystal Mail after a battle with a Behemoth. Backtrack to the last room, this time going north. In the next room, go northeast to pick up a pair of Crystal Gloves after a battle with two Red Dragons. You will reach the next door by going west. Pick up the White Robe in the next room and continue north. The chest in the northwest corner has an easy battle and a Crystal Helm. To continue, go down the staircase in the southeast corner.

Crystal Sword
In the next room you reach, you will find two parallel bridges. Go down the one on the left, and cross an invisible bridge all the way west. Once across, go north then east through another invisible passage, and finally south down a hidden stairway. In the next room, head east, until you reach the teleporter. Continue north two flights of stairs. On the third flight pick up the Protect Ring (after a battle with a Behemoth), then continue north to the teleporter. At the save point, prepare to fight a boss (use two or three tents if you have a lot, or a cottage).

Dark Bahamut
Dark Bahamut (Wyvern) begins the battle with a Mega Flare (Mega Nuke) attack that often kills some weaker characters, and then casts Reflect (Wall) on itself. Heal up before attacking in earnest. Never use summon spells on Wyvern, as he counters with more Mega Flare attacks. Instead, have Rydia cast Quake, since that bypasses Wyvern's Wall. As long as you don't trigger additional Mega Flare attacks, Dark Bahamut is simple.

Once you defeat this boss, you can have Cecil equip the Crystal sword. Go backwards to the room with the invisible bridge, and the two divergent bridges.

Towards the Core
This time take the bridge on the right, and through the door around the path. Go through the door on the right in the next room. Finally you will come upon a save point in the first door you reach. Use this point because it is very important to be healed for the remainder of the game.

Holy (White) Lance
Leaving the save point, go into the next room on the right, and you will find the Holy Lance. Plague Horror is difficult to defeat, as it places a 10 second instant death countdown on all characters. You have to defeat it before your time runs out. Since Plague is a flying enemy, Edge's boomerang weapons, Rosa's arrows, and Kain's spears all do extra damage.

Alternatively, you can exploit the AI. Any time Plague notices a character without the countdown timer, Plague recasts the countdown, but this resets everybody's countdown to 10. Therefore, you can kill and revive a fragile character like Rydia over and over to force Plague to repeatedly refresh everybody's countdown timer.

For winning, you get Kain's most powerful Spear.

Ribbon
The next room to your right contains two chests. Before you are able to open them, an enemy will attack you. These two dragons are not too difficult to defeat. If you use magic on them, they will remedy themselves, but Rydia's Bahamut is pretty effective, as it is far stronger than the remedy. You can't use magic on them because they cast Wall. Otherwise, simply use the strongest attacks possible. Finally, once you have defeated these enemies you are ready to move on to the final stage of the game in the Lunar Core.