The party tracked the green slaad via the modron compass but couldn’t see it among the tribal villagers enacting some ritual. But on scouting ahead the warlock and gnome realized that the tribesman with the staff that became a sword really was the slaad, but it was looking more grey than green. The party got reinforcements and attacked. The modron perished but so did the slaad.
Oh, they set the jungle on fire and scared the villagers off. Probably for the best, really.
Then their airship went above the clouds except a cloud docked with them. A large blue lady (a cloud giant!) welcomed them with food and they were invited to the court of Lord Agneol, who needed their help with his troublesome brother Bagneol, to rescue Agneol’s niece Hypatia. The party agreed to issue the official challenge to Bagneol.
Also the party arranged to free the air elementals in their ship, remove all the other sigals (including communication, sudden release of said air elementals (could have been mid-flight!), etc.) and replace it with a magic cloud. They did promise to try to free all the other air elementals (otherwise there will be war within a year!).
This took a few weeks. But the party should be ready for the challenge soon.