Rowan quickly brought out the remaining two treasures, which were the Aeorkron Core, a Universal Bearer Level Treasure, and the Ruin of the Mountain, and Sea Supreme World, a Proto–Source Level Treasure.
Each treasure here was integral to his success, as he had chosen to build his Destroyer Core to be patterned around these treasures, if he had a different set of treasures then he would still change his style of refinement to reflect what he had to work with.
What Rowan considered to be the most important metier for him was the direction the Core was being crafted towards, and not necessarily the materials, although a powerful enough material as the base was a plus.
Unlike the Gears of Madness, these two treasures had a unique method of refinement, and with the differences they had, he flowed according to his plans.