The Elder Melder — Monster Hunter: World Walkthrough

The Elder Melder is a crucial NPC in Astera who can transmute unwanted decorations or streamstones into new ones. This is a primary method for obtaining rare decorations in the endgame. You can use different melding options, such as 'First Wyverian Ritual' or 'Ritual of the Melding Pot', which require different materials and offer varying chances of rare decorations. While it's still RNG, it provides a way to utilize duplicate or unwanted items to potentially get what you need for your builds.