Virgil, from Ultima IV
When the Stranger met Virgil, he was surrounded by poison fields. The Stranger had to pass through them in order to talk to Virgil. Virgil then said that he created magical fields, poison being his favorite (as it could be clearly seen). Following a tip from Arron from Vesper, the Stranger asked Virgil about nightshade. Virgil said that it could be found only in the darkest of night, at the coordinates lat-J'F" long-C'O".