After landing at the mainland as Celes and arriving on the Serpent Trench you have the option of travelling north or south. Go north to find Nikeah, or go south (and a long way east) to find Mobliz. It's no longer part of the Veldt, so you won't find much else of interest out here.
Mobliz is not looking so hot these days, though there are still people about. Follow the boy who flees into the town and, in the basement of the old post office, you’ll find the remaining population... guided and cared for by Terra. Try as you might, though you can’t convince her to leave with her, and eventually you'll have to leave.
A cut scene follows. Once it does...
Humbaba
HP: 26,000
Weakness: Poison
A demon of the old world that is back to plague the new world, Humbaba is a constant thorn in the side of Mobliz. He uses the following attacks:
- Normal physical attacks
- Solar Plex, a stronger melee attack
- Thundara / Thundaga, Lightning spells
- 1000 Needles, a spell that always inflicts 1,000 HP of damage to a single target
This battle begins with Terra fighting Humbaba solo. She can’t do any damage, regardless of how you proceed. You need to lose. Let Humbaba take Terra down.
Your party shows up for the second round. If you’re fighting with only Celes, this can be a rather dangerous fight; if you have even one other person it’s not so bad. Humbaba uses physical attacks and Lightning spells to assault your party, though he’s not terribly tough. Your best bet for driving him away is to use Poison spells / equipment (Poison / Bio as spells, Venom Claws as weapons on Sabin) which target Humbaba's natural weakness to the element.
Do enough damage and Humbaba runs away. Recuperating in bed after the battle, Terra confesses her confusion and refuses to accompany your party until she's done some thinking. You’ll have to come back later. On the plus side, you’ll receive the Fenrir magicite.
Leave Mobliz altogether. If you’re still hoofing it as Celes / potentially Sabin, you’re done here for now. If you have the Falcon, though, you can immediately reenter Mobliz and trigger the next part of this recruitment.
There are problems in Mobliz. Speak to the kids, then enter the house on the west side of town. A dog entering the house reveals a secret chamber behind the bookcase in the house. After the cut scene is done (and after you’ve checked a pot in here for a Hi-Ether) you’ll have to rush outside. Time for round two!
Humbaba
HP: 26,000
Weakness: Poison
Yep, this dude again. Humbaba has slightly stronger stats this time around, but he’s otherwise identical. Do enough damage and he’ll blow two of your characters right out of the battle. Once that happens Terra rushes in to join your remaining two characters in fighting Humbaba, and she’ll do so under the permanent effects of Trance. She can now dish out damage again, and thanks to Trance does much more damage than normal. Let Terra handle the offensive part of the fighting, casting Poison / Bio, while your other two characters back her up. The fight doesn’t change a whole lot overall.
Defeat Humbaba to trigger a touching cut scene between Terra and the kids of Mobliz. She'll rejoin the party once it ends, and remains with you for the rest of the game. (And don't worry about any party members Humbaba blew away during the fight - they're back on the airship.)