When the mage Sulman betrayed King Roland to the kreegans, Xenofex gave him a letter and told him to travel to New Sorpigal and show it to Andover, who would give him a reward. On the way there, Sulman was ambushed and slain by a pack of goblins. The letter ended up in the hands of a party of adventurers.
Andover can be found in the A Lonely Knight inn in New Sorpigal. The party can talk to him and show him Sulman's letter to end the Show Sulman's letter to Andover Potbello in New Sorpigal quest. This will immediately start the Bring Sulman's letter to Regent Wilbur Humphrey at Castle Ironfist quest.
Andover is the questgiver for the Retrieve the candelabra for Andover Potbello quest. When the cult left the abandoned temple near New Sorpigal, they left behind a candelabra that was used in their rituals. None of the priests dared to go back, so Andover asked the party to retrieve it.