When the Kingdom of Avernum discovered Upper Avernum and set its sights on the surface in 831 IE, Anaximander of Unspecified Services recruited a number of agents to scout out the surrounding area in Valorim. Among these agents were several parties of adventurers. The first party met with a grisly fate, but the second party achieved success on an epic scale. They defeated the plagues of Rentar-Ihrno and are largely responsible for the reconciliation of Avernum and the Empire. It is this second party that is most commonly referred to as the Surface Explorers.
The First Party
The first party consisted of four adventurers, Erin, Elsner, Gwost, and Tucker. They were trained briefly, and given the powerful Xian Items by X. Confronted with the vastness of the surface, the four split up in order to cover more territory, and were not heard from until the second party was sent out.
Their fates were mostly quite grim. Erin investigated the slimes in Krizsan Province and died in the Slime Pit. Elsner investigated the cockroaches on the Isle of Bigail and was killed in the Filth Factory. Gwost was killed investigating the sliths in the Golddale mines. The only member to survive was Tucker. He was ambushed by troglodytes when heading to Sharimik, but he escaped and hid in Softport until he was able to contact the second party. After recovering from his injuries in Upper Avernum, Tucker returned to the surface to do more work for Unspecified Services.
The Second Party
The accomplishments of the second party were epic in proportion. Their most significant achievements included the eradication of Rentar-Ihrno's six plagues and saving all of Avernum from Grah-Hoth in the aftermath of the Tower of Magi disaster. Eventually, with help from Erika Redmark, who was martyred in the process, they destroyed Rentar's machinery and won a place in the sun for all Avernites.
Other accomplishments they are sometimes credited with include negotiating with Empress Prazac on behalf of Anaximander and King Micah, recovering the Orb of Thralni from the Cult of the Sacred Item, clearing out many minor menaces, including goblins, bandits, undead, ursagi, and the like, and collecting various magical artifacts from around Valorim.