All seems well here. It would make sense to check in with King Giott, though.

The EasyType changes Giott's てにいれんがため (te ni iren ga tame) to its standard equivalent, てにいれるため (te ni ireru tame).

One small problem, though. How do they get there? Maybe someone has an idea.

Good idea, but he blew himself up. Unless...

And sure enough, snoring away down in the infirmary...

Number of times someone has survived apparent certain death: 6

Cid wakes up as the others approach.

Again, Rydia's using an affectionate family term that probably shouldn't be translated so literally, except that I've headcanoned that she's "adopted" him.

Anyway, Cid's line is more interesting. He uses the passive form of the idiom 尻に敷く (shiri ni shiku, literally "sits [her] butt on [him]"), which is largely equivalent to the English "henpeck". This not only suggests that Edge doesn't dare cross her, it also implies that they're a couple. And I can't say there aren't already signs of some belligerent sexual tension between them, though some of the quipping back and forth was dropped in the English version, likely mostly for brevity.

Cid's theme starts and he quite literally leaps out of bed. The dwarves don't take well to that.

He heads out the door, dragging them with him.

A textless cutscene follows, with Cid rushing around the airship deck directing the dwarves, then dragging Edge onboard to help, though they seem to spend as much time arguing as anything else. And one of the dwarves nearly falls off the pier before the scene fades out...

Back in the infirmary, Cid is back in bed, where he probably should have been the whole time.

Sad music starts playing, but...

...he didn't work himself to death, just dozed off.

Now the Falcon can fly over magma, opening up several new areas. There's a cave in the northwest, another cave on an island in the west, a town and cave southwest of the castle, and an isolated house in the southeast. Don't forget the healing pot in the castle's back entrance, either.

There's something of a curious oddity in how monster encounters are zoned down here. The underworld map is divided into 16 regions, with a 4x4 grid, which so far is typical and unremarkable. The nine zones toward the top right, which is everything you can reach without an airship, have one set of encounters, including the monsters Armed Mammal (Armadilo), Goblin Captain (Dark Imp), Black Lizard (BlackLiz), and Magmantoise (Tortoise). Most of the zones along the southern and western edges have a second, different set of encounters, including the monsters Blood Flower (TrapRose), Chrysalis (RocLarva), Hell Flapper (RockMoth), and Undergrounder (Centpede). Again, no big deal. One set of encounters pre-airship, another set post-airship for the second time underground.

However! The zone just below the top left one, which covers only the southern edge of the northwestern landmass and a tiny bit of land along the wall south of it, has its own unique set of encounters, including the monsters Blood Flower, Gloom Wing (GlomWing), Misleader (Crawler), Medusa, Gorgon, Stone Golem (Stoneman), Alraune (Talantla), Coeurl (BlackCat), and five different varieties of eggs that may hatch into Black Lizard, Lamia, Naga Raja (HugeNaga), Green Dragon (Green D.), or Yellow Dragon (Yellow D). And the Gloom Wing, Gorgon, and Alraune don't appear anywhere else in the game!

First, the house in the southeast. In the main room are two apprentices.

Upstairs, the master won't get out of bed.

The EasyType replaces うたん (utan, won't forge) with つくらん (tsukuran, won't make), presumably because there are several different うつ (utsu) verbs.

Search his shelves for a Soma Drop (or Elixir in versions without those), and walk rightward through the wall after coming downstairs to find a chest with some money. Other than that, there's nothing else to do here for now, but it's worth keeping in mind if any Adamantite turns up.

The town features a weapon and armor shop with new equipment (mainly diamond armors), a few minor treasures for the taking, and more chatter and rumors.

Although I can understand wanting to use "sylvan" as an adjectival form of "sylph", I'd expect a sylvan cave to be in the woods, or full of trees.

Note that this cave can be saved for later, or even skipped entirely, but you'll miss out on some rewards if you wait too long...

Parts of the floor glow and will damage the party if stepped on. Rosa can cast Levitate (Float) to avoid this, but note that it wears off after moving to a different level of the cave. If Rosa hasn't learned Levitate yet, it's probably a better idea to leave for now and come back later.

The cave is loaded with treasures, though most of the chests with interesting prizes also contain nasty monsters.

Speaking of nasty monsters, the cave has quite a few of those already, particularly the Malboro with its trademark Foul Breath attack. Note, however, that immunity to any of the status effects it causes blocks the entire attack. Relatively little equipment gives status immunity, especially before the endgame, but the Rune Bracelets sold in the castle prevent Silence and can keep at least your mages and ninja protected. The fighters can use the Ruby Ring (prevents Pig) if you kept any after clearing the Magnetic Cave, or the Giant's Bracer (prevents Minikin) if any ogres or golems happened to drop one.

Furthermore, the Malboro is itself vulnerable to many status effects, including Toad, which will completely neutralize it as a threat. Maybe the occasional Toady Witches and Toady Toads in the cave were meant as a hint? Regardless, have Rydia hex them, and then Edge can steal a healthy stockpile of Panaceas.

After going down the first set of stairs, take the north stairway for a route riddled with secret passages that eventually leads back outside, with the Faerie Rod along the way (unguarded) and the Full Moon and Avenger in a cluster of six chests (all six with monsters inside) right before the exit.

The Faerie Rod has the second best intelligence bonus of any weapon, and its item effect reliably Confuses enemies that aren't immune.

The south stairway instead leads to a save point, with the Elven Bow through a secret passage north of it, then the Mage Masher through another secret passage on the floor beyond it. This route eventually leads the party to an unexpected house deep in the cave. The Sylphs mentioned in town live here.

Oddly, treasure chests nearby contain a Cat Claw and a Hell Claw. Or perhaps it's not so odd, because there's a familiar figure resting in bed...

Number of times someone has survived apparent certain death: 7. And this is his second time!

Sure enough, Yang is completely unresponsive.

There's nothing more to do here for now. A teleporter upstairs conveniently leads back outside.

There's one of the weaknesses of translating げんじゅう as "summoned monsters". It's far too generic. Add in the tendency to abbreviate everything due to space limitations, and you get things like this cave, where what was supposed to be a special term turns into just an area full of monsters. But isn't every area?

Note that this cave can be saved for later, or even skipped entirely.

Like the Sylph Cave, this cave has some glowing floors that will inflict damage unless using Levitate to avoid them. Additionally, the remaining floors are see-through, showing the next lower level of the cave, which can be a bit disorienting until you get used to it. Also like the Sylph Cave, there's a good deal of treasure here, including the Defender, the Poison Axe, and Edge's strongest general-purpose weapon yet, the Kikuichimonji. Only the Defender is guarded.

The monsters here generally aren't as bad as in the Sylph Cave, though. Of particular note is the Summoner, which summons another monster, then replaces it with another of the same if the summoned monster is slain. It's great for farming, and may be the best chance to win a Goblin summon item.

Secret passages normally look just like solid walls in the original Japanese version, but here in this cave, they're instead partially see-through in all versions, revealing themselves by showing glimpes of the level below when there's anything below them to show.

Deep inside the cave, a teleporter leads to an area inhabited by NPC monsters, with a different look that seems more like deliberate construction, and featuring different music. These monsters are particularly friendly to Rydia, and no random encounters occur here.

One more teleporter leads to the town proper.

The main town includes an inn, a save point, and weapon and armor shops with new equipment.

Yes, there's a library, too, full of readable books.

The English version is completely unrelated, presumably due to the item being removed. The EasyType has yet another completely different message:

This brief story is the only mention of a whale in the original Japanese text. It at least sort of explains something in the English version later on.

The EasyType makes a small change, replacing たいこのそら (the ancient sky) with むかし　そら (the sky long ago).

The EasyType adds かいふくまほうの to describe her power, specifying that it's the power of recovery magic.

Another teleporter in the library leads to a distinctive chamber.

It's fairly obvious who the king is, but he denies everything.

So Queen Asura will have to come first.

Asura is sort of a puzzle boss, with three faces that she cycles between and a spell for each one: Protect (changed to Cure4 in the English version), Cureda, and Raise. Each time she uses a spell, she switches to the next face; each time she takes damage, she attacks and switches to the previous face. As the book in the library suggests, using her power is key to overcoming her. But how? Simple! Cast Reflect on her and watch as her magic bounces right off.

Reflect may need to be renewed every so often. Asura's strikes are surprisingly strong, but note that she only attacks as a counter, so holding back on damaging her will keep her from attacking you. Finally, she's flagged as a Mage, so weapons like the Mage Masher and Rune Axe will provide quadrupled attack power, and by the same token, the Aegis Shield sold right here in town and the Rune Bracelet sold elsewhere will halve her effective attack power.

It's possible to win without using the Reflect tactic, particularly if you carefully manage her state to keep her using Raise and only Raise as much as possible. Absolutely use Slow to delay her turns and Haste to speed up your attackers if attempting this. The English version complicates things by giving her another healing spell in place of Protect that can fully restore her health, though at least the full heal effect that Curaga (Cure 4) has when single-targeting is also glitched for large values such that it starts overflowing and recovering MP instead once she's damaged badly enough (more than 16,384 damage taken).

With Queen Asura defeated, King Leviathan is willing to talk.

Leviathan is distinctly not a puzzle boss. He just hits hard and fast, using Greater Tsunami (undefendable damage = 25% of target's max HP) and Blizzara. He's predicably weak against Thunder, and has no other resistances or weaknesses.

There's not much depth of strategy to be had here. Stay healed, use Slow and Haste to help compensate for his speed, and Berserk the fighters if you get the chance. Asura could come in handy as an emergency heal, but might waste Rydia's turn and MP instead. Have Edge use the Thunder Claw with the Kikuichimonji for best results. Rydia can use Thundara or Ramuh for damage, and Cecil and Cain mostly just attack with their strongest weapons.

On the way out, there's a Rat Tail in a chest by the teleporter to the outskirts of the town. Better hidden is a nearly invisible teleporter in a nook on the south side of that floor. This leads to a group of four chests that include Yoichi's Bow. The treasure room also has another stealth teleporter that leads back outside.