No cores can be put onto this card except by it's own effect, including when it is deployed.
[LV1][LV2] When you pay the cost and summon a Brave in the family "Exalted Sword", put 1 core from the void to this Nexus.
[LV2] (Your Main Step) When there are 5 or more cores on this Nexus, you can summon 1 Spirit card in the family "Fusion Beast" from your hand, without paying the cost. This effect can only be used once per turn.