[LV1][LV2][LV3] (When Destroyed/Depleted by the Opponent) Return a Blue-only Nexus/Grandwalker Nexus from your Trash to your Hand.
[LV2][LV3] (Your Attack Step) When your "Sandsea"-named Spirit is destroyed/depleted by the opponent, put one core from the Void to a Blue-only Nexus/Grandwalker Nexus you control.