Dust 8

A plane crashes and 8 people survive – and they shouldn’t have save for the fact that the mountain has an unusual magical property and the survivors were all hit with rocks from the mountain during the crash. As long as they keep those rocks, they stay alive. But the guardian of the mountain sends two people after the survivors to get the rocks back, in the disguise of two children killed in the crash. Originally under the title "Dust 18" (and was meant to be 18 chapters). It was not popular during serialization, and thus was not able to properly conclude. It was later reworked and touched up as "Dust 8" when it was collected in the Tezuka 400. (Tezuka's afterword)