(Examination)
It's a frog Titan, one that can shoot fireballs; I'm surprised Darkerdark even told us that much. I wouldn't be surprised if it can shot an elastic tongue along with fireballs and quite possibly shoot an elastic flaming tongue. If anything it can also probably gather up more than a group of elves with its tongue.
I would also guess that the creature has to be at least two and a half or maybe just two stories high. So I.E. the titan has to be at least thirty-nine to thirty feet tall. That's 11.887 meters or 9.144 meter for you metric people. If this is going by DF rules our elves should average around five to six feet tall or 1.5 meters to 1.8. I also doubt that Amala can handle a titan; don't get me wrong, it's unlikely she's lived long to have fought something like that.
(Conclusion)
If we are going to fight something like that, the only way the elves could defeat it is to use it's natural weaknesses, but than again, this is a titan. I doubt it has any conventional weaknesses, not to mention that the salt angered it in the first place or at least the fighting. So I doubt that it's even worth it to try and fight it.
(Idea)
The only real option at this point (if the frogs are not the creature's keeper) is to blame the frogmen. Judging from the Titan's words, it's probably not happy to see anyone. I would offer one of those elephants (a live one and less drugged one, maybe) as a snack to it and try to explain that the frogmen started the whole fight in the first place. Hopefully if things right, the frog titan should kill all the frogmen clear a path for us and let us through and have us never come back.