Edgar: Locke!
Locke: I know... "Someone" has to sneak into South Figaro to slow down the enemy, right?
Edgar: This is right up your alley. We're counting on you.
Locke: Terra... Wait for me... I won't be gone long. ...And watch out for a certain lecherous young king who shall remain nameless. The guy moves in like a hawk!
Edgar: Locke!
Sabin: Edgar... Old habits die hard, eh?
Banon: What about us?
Edgar: We can escape down the Lethe River and make our way to Narshe. I'm curious about that esper they found in the mines...
Banon: Very well. I'll ready the raft by the back entrance. It's risky, but we don't have much of a choice at this point.
Edgar: It's not safe here. Come with us to Narshe... It could be a chance for you to gain a better understanding of your abilities.
Banon: We've no time to dilly-dally. Let's make for Narshe!
If Terra says no three times, eventually Banon gives up asking, and the meeting is skipped. Just as Terra expresses her doubts in her own abilities to provide hope to anyone, the wounded Returner stumbles in with the news of South Figaro (and the Genji Gauntlet). And since Terra can't just hang around, she escapes to Narshe with everyone else.
If you say yes to Banon straight away, he gives Terra a Gauntlet and the Genji Glove becomes unavailable. The Gauntlet allows Double-Grip instead of the Genji Glove's Dual-Wield. Gauntlets are in short supply (while Genji Gloves are theoretically infinite in number) but Genji Gloves allow for higher damage output overall.
Anyway, Banon signs up into the active party. You can tell he won't stay long, because he didn't get a custom name screen. His Pray ability doesn't scale well, either; it's a free Cura. That's plenty enough to keep everyone in top shape now, but if it lasted into lategame, no one would ever need Curaga.
No Phoenix Downs allowed! Once Banon hits 0 HP, everyone gives up and goes home.
So there are, of course, battles to be fought to give Banon a chance to die.
There are branches to take, but all of them lead to the end, so
The second branch leads to a loop. If you go up, the raft travels in a circle and you get the same prompt again. This allows an infinite number of random battles, in case you want to level up Banon a bit
Or set your Config menu to "Memory", put Banon on Pray duty and Edgar on the Autocrossbow, and strap down the controller button overnight. Banon will keep everyone healed up in random battles while everyone else kills monsters, and without any further oversight you can come back to the game at level 30 or so. Or spend two days doing it for level 50 or so. Or whatever.
I do zero loops, incidentally.
Another short cave with a save point and we're nearing the end of the river area.