Bafsk

With the Mythril delivered, return to the Rebel Hideout and talk to Hilda. Ask about Dreadnought. She'll task you with going to Bafsk. 3 chests in Bafsk Cave.

Bafsk

Take the Canoe across the lake back to Paloom and speak to the pirate to take the boat to Poft. Pay 200 Gil to fly to Bafsk, or walk around the mountain.

Bafsk is Imperial territory. The magic shop (bottom right corner) sells Esuna and Basuna. Esuna cures status ailments; you'll need it constantly from here on. Teach it to Firion.

Walk south until you spot a lone soldier. Ask him about Wild Rose first to prove you're a rebel, then ask about Dreadnought. He steps aside and reveals a hidden passage.

Bafsk Cave

Bafsk Cave is a short dungeon: 2 floors, 3 chests, no boss.

B1. From the entrance, head up the passage to find a Longsword. Go back down and follow the path right. It curves around to the bottom left corner where a Longbow sits. Continue right and take the exit to B2.

B2. Go right and skip the first intersection. Keep going right, then up. The path zigzags in a lightning bolt shape; follow it until you see light coming through an opening. A Dark Knight blocks the way.

A cutscene plays with the Dark Knight, Borghen, and the Dreadnought. Head back inside the cave and go right through the door to pick up the Pass. Walk to the right and use the purple teleportation pad to warp out.

Learning About Sunfire

The teleporter drops you outside Bafsk. Walk north around the mountain, keeping it on your right, until you reach Poft.

Speak with Cid and ask him about Dreadnought. He'll mention Sunfire. Learn this keyword and ask him about it.

Return to Altair and talk to Hilda. Ask about Sunfire. Exit the room and go to the room on the right. Speak with the King and ask him about Sunfire. He'll explain that Sunfire is in Kashuan Keep. But you need the Goddess's Bell to enter. Learn the keyword and ask him about it.

Speak with Hilda again in the throne room and ask her about Goddess's Bell. She'll direct you to Josef in Salamand.