New campaign

Yesterday was the first session of a new dnd campaign that I'm running.
Everybody seems to have made a sport of playing the strangest character classes which they could find and now we're lacking an (decent) arcane caster. We have a swashbucling pirate, a very specialized shapeshifting druid, a dilletant (whose key asset at the moment is his saves), a duskblade speciallizing in geography, then a cleric and a rogue.

The world that they're playing on is home grown. I still have to come up with a name for it. It's basicly a world where evil has been erradicated long ago. At first there was the great nation of Devalon which covered a significant part of the world. But after the king dissappeared, some of the more distant cities severed all ties, forming the nation of Katarna. Since then tensions has been rising between the two great nations.
Our heroes began on various different places but all met with an untimely death in the first few moments of the session. However shortly after they woke up again near the towns of Smallbank and Treeshine on the border between Devalon and Katarna. They soon find out that strange things have been happening in this area and random attacks are taking place on nearby farms. When a witness steps forward in Smallbank who claims to have witnessed that the elves of Treeshine are behind the attacks, the town starts gathering weapons. Determined to stop a war, the heroes set out to investigate. After finding some strange ruins in the area, they head out to Treeshine. In Treeshine they discover that a witness there has claimed that the people of Smallbank are behind the atrocities and that there too they are readying for war. Now our heroes are sure that a third party is involved, whose bent on starting a war in this area. This all coincides with the discovery of an area of forest where everything has turned evil, a sight unseen for thousands of years. The session ended with the investigation of ancient crypts. Legends surround these abandoned crypts, and some claim that the recent events can be traced back to them. After navigating several traps and discovering an unorthodox transportation system, the heroes find themselves in a hidden underground giant city, a race unseen for millennia.