The Smelting Tutor (named Feoras) was one of several tutors stationed in Lumbridge. He provided information about Smithing to both new and advanced players. If you look at him closely, you will realise that he is shorter than normal Male adult NPCs. This has often confused players as no one has stated why he is smaller.
He is currently seen working the bellows in Lumbridge, and can no longer be talked to due to an update that removed the use of tutors.