Ocarina of Time
In Ocarina of Time, Medigoron is Biggoron's younger brother. He makes the Giant's Knife at Medigoron's Blade Store and sells it to Link for 200 Rupees. Despite its size, and how long it took to make, the Knife breaks after striking it eight times or four times if hit at enemies. It is considered a "small" weapon by Medigoron.
In Majora's Mask, Medigoron works at the Goron Powder Keg Shop, which is located in the Goron Village, where he makes the insane Powder Keg. He is also the instructor of the traveling Goron who sells Powder Kegs in the Bomb Shop in Clock Town. Medigoron gives Link a Powder Keg Certification after he completes the test on proper usage of Powder Kegs. The Certification proves that Link can purchase Powder Kegs. After the test, however, Medigoron admits that the test is very dangerous and gives Link a free Keg to apologize.