Power Keepers is a set in the EX series. It was released on February 2, 2007. The printed size is 108, and the checklist is the same length. Darkness Energy is 87/108, in position 87 of 108 on this checklist. Before it is 86 Root Fossil, and after it is 88 Metal Energy. The listed rarity is Rare.
Darkness Energy is an Energy card. It is listed as Special.
Milky Isobe illustrated this card. The same name is on 22 other cards in the catalog.
The card text says: If the Pokémon Darkness Energy is attached to attacks, the attack does 10 more damage to the Active Pokémon (before applying Weakness and Resistance). Ignore this effect unless the Attacking Pokémon is Darkness or has Dark in its name. Darkness Energy provides Darkness Energy. (Doesn't count as a basic Energy card.)
I keep a set binder for Power Keepers, meant to hold every card of that set. This card is one slot in the Power Keepers set binder. I still need this card.
If the Pokémon Darkness Energy is attached to attacks, the attack does 10 more damage to the Active Pokémon (before applying Weakness and Resistance). Ignore this effect unless the Attacking Pokémon is Darkness or has Dark in its name. Darkness Energy provides Darkness Energy. (Doesn't count as a basic Energy card.)
Power Keepers, in the EX series. It was released on February 2, 2007. The printed size is 108.
87/108. It is entry 87 of 108 in this checklist.
Milky Isobe. The catalog lists 22 other cards with that illustrator.
Rare.