Water Crystal
Jin promised rebuilding and he had already begun to keep his promise as soon as the workers had completed what they had been doing for the past two weeks. With the excavation of Portal 5, all the crystals in the dungeon had been used in improvised smithing. It was way less than the gigantic mine that Ress had underneath it but it was extensive enough to be used for improvised smithing.
The King had worked on it for 1 hour, pouring Maqi into it, as usual, to strengthen and enhance it in a way that it had become the world's super sucker when it comes to water. Not only that, with his focus on desalination making the sea water into clean drinkable water for humans, the crystal was able to do so with a 1:1 ratio, producing salt as a by product too.