I Think So Too
Yanvlal and Krune decided to use some low-level Diamond Stars materials. Although it would still be somewhat expensive for them, it would all come back when they put the completed equipements for sale. Swords, Shields, Spears, Yanvlal Surrigel created several types of equipments with Krune's Purple Flames.
They also sent every completed work directly to the Blacksmith Organization. Sure enough, when they started to get those Diamond Stars Purple Flame items, they felt frightened. But they soon found out that the one forging them was a Diamond Stars Blacksmith. Krune was just providing the Purple Flames itself.
In fact, they aren't as good as if Krune had made them himself. After all, as well synched as Krune and Yanvlal work could be, there is bound to be some problems. Too bad that Krune was far from being able to create Chaos Energy, so he could only use this method.