Light Stone, Pure Star Marrow, Pure Star Source are all considered the highest soul elements for humans, among which Pure Star Source is the most versatile and widely applicable. The Pure Star Source Potion it produces has an incredible enhancement effect on everyone, largely contributing to Trolian's current strength, thanks to the Pure Star Source Rod and his companions brought back from Horror Castle.
The usage of Light Stone is narrower, currently only effective for those whose soul trait includes "light." High-efficiency applications similar to Pure Star Source Potion have yet to be developed.
Pure Star Marrow is similar; its only current use is Rod's creation of [Kales' Soul Cannon] or activating [Spirit Boat] for routine teleportation gates, with no precedent of use for humans.
