Senecus

Senecus was an elderly man who lived in the village of Havenmere in the 14 century DR.

History
In his youth, Senecus served a wizard as an assistant and cleaner. Although Senecus didn't gain any magical abilities, the wizard did enjoy chatting with him on a wide variety of arcane topics, giving Senecus a broad (but shallow) understanding of common and obscure magical phenomenon.

When Simon Weems and the Demon suddenly appeared in Havenmere, Senecus was struck by the resemblance of the event to a "spontaneous gate", a naturally-formed gate that appears and transfers something from one world to another, with an equivalent exchange in the opposite direction. He further noted that the event involved two worlds connecting to a third, creating a "vector balance" between the two planar travelers. He surmised that if Weems and the Demon were reunited together, the gates would reform and send both of them home.

Senecus' analysis proved correct, and some passing adventurers hunted for the Demon in order to unite it with Weems, hopefully returning them to their proper planes.