Darkness Energy is an Energy card. It is listed as Special.
Darkness Energy sits at 79/90 in HS—Undaunted, position 79 of 91. Before it is 78 Team Rocket's Trickery, and after it is 80 Metal Energy. The set belongs to the HeartGold & SoulSilver series. It was released on August 18, 2010. The printed size is 90. This checklist is longer, at 91 cards. The listed rarity is Uncommon.
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 if the Pokémon that Darkness Energy is attached to isn't Darkness. Darkness Energy provides Darkness Energy. (Doesn't count as a basic Energy card.)
The illustrator line reads Kent Kanetsuna. I count 74 other cards in the catalog with that illustrator.
HS—Undaunted set binder is where a full HS—Undaunted set goes. This card fills one slot there. 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 if the Pokémon that Darkness Energy is attached to isn't Darkness. Darkness Energy provides Darkness Energy. (Doesn't count as a basic Energy card.)
HS—Undaunted, in the HeartGold & SoulSilver series. It was released on August 18, 2010. The printed size is 90.
79/90. It is entry 79 of 91 in this checklist.
Kent Kanetsuna. The catalog lists 74 other cards with that illustrator.
Uncommon.