This Spirit card in your hand can be summoned at no cost when your opponent increases core from the void outside of their core step. After that, for each increased core, send 2 core from your opponent's Spirits/Ultimates to the void.
[LV2][LV3] (Your Attack Step) When opposing Spirits or Ultimates are depleted, you can return this Spirit to your hand.
Ruling: This Spirit cannot affect the cores obtained from Core Charge, but they can affect cores a Grandwalker Nexus puts in other places (Cards on the field, Reserve and such).