Melchior is a character from Chrono Trigger. He is known as the Guru of Life.
Crono first meets Melchior at the Millennial Fair in 1000 A.D. Melchior refers to himself as a swordsmith and takes an interest in Marle's pendant. He also has a shop on the Eastern continent. At this point in time, Crono has no idea that Melchior will play a major role in the journey ahead.
After acquiring their magic powers at The End of Time, Crono and his party end up in Medina in 1000 A.D., then head west to find Melchior's Hut. There they meet Melchior again. He tells them that they can reach the Northwestern continent by going through Heckran Cave.
Now on a mission to repair the Masamune after acquiring the broken pieces, Crono and his party return to Melchior's Hut. Melchior explains to them that it can only be repaired using a red mineral called the Dreamstone, but it hasn't been around for many, many years.
Upon their arrival at Melchior's Hut, Crono and his party present the red mineral to Melchior. He immediately begins work to repair the Masamune sword. When it's done, they leave and travel back to 600 A.D. to find Frog.
Attempting to rescue the Guru of Life, Crono's party journeys up the Mountain of Woe in 12,000 B.C. to defeat the monstrous Giga Gaia and rescue the Guru. It's then that they realize the Guru of Life is Melchior. Since the Giga Gaia was destroyed and the seal had been broken, the mountain was collapsing. They all got off the mountain safely before it fell into the water.
After the Rainbow Shell is recovered and Yakra XIII is defeated in 1000 A.D., Melchior arrives at Guardia Castle to use the Shell, combined with the Sun Stone, to create stronger weapons for Crono's party.