Oziach

Oziach is a non-player character located in a small house west of Edgeville. In the house is a chair and a bed. He seems to speak with a peculiar drawl or accent, and is acquaintances with notable people of Gielinor such as the Champions guild master and the Duke of Lumbridge. He is the only NPC source of the rune plate mail body.

Dragon Slayer
When asked if he can sell the player a rune plate mail body, he tasks the player with eliminating the dragon Elvarg from Crandor during the Dragon Slayer quest to prove their worth. The player is given this task because Oziach doesn't want the unworthy to be wearing his precious and rare armour.

After completion of Dragon Slayer he will sell rune plate mail bodies to the player for 65,000 Coins each.