The item is called Thunder Essence in Castlevania Puzzle: Encore of the Night and raises one's lightning affinity, although it doesn't help unlock Lightning spells.
|Item Data: Resist Thunder|
|Image||Name - Game|
|Type / Users||Attributes / Consume||Statistics / Sell||Found||Notes|
|Resistance to lightning [use]|| Medicine (Attribute Potion)|
| Attrib: Thunder|| Find: Alchemy Laboratory, Floating Catacombs, Reverse Keep|
|Gain resistance to lightning.|| Enchanted Soul|
| Rarity: ***|
|Increases your affinity to Lightning for one battle. Does not unlock spells|| Item (Medicine/Attribute Potion)|
| Attrib: Lightning affinity +10|
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