Doctor Orbon is located in the East Ardougne chapel, and is involved in the Sheep Herder Quest. He sells the plague set, consisting of a plague jacket and a pair of plague trousers, that protects players from the poisonous sheep. He seems to be a scientist who has invented a suit that helps protect people from the infected sheep around the north of East Ardougne. The quest cannot be completed without his help.
If talked to while wearing full mourner clothes, he will ask for his payment, saying 'he won't keep the charade any longer for free', and asks to tell the head mourner about it. This implies that he is part of the Mourners or is working for them.