As long as Rocket's Entei ex has any Darkness Energy attached to it, Rocket's Entei ex has no Weakness.
Attacks
[Colorless]Energy Link
10
Energy Cost: 1
Search your discard pile for an Energy card and attach it to Rocket's Entei ex.
[Fire, Fire, Colorless]Volcanic Ash
Energy Cost: 3
Discard 2 Energy attached to Rocket's Entei ex and then choose 1 of your opponent's Pokémon. This attack does 60 damage to that Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.)
Weaknesses
Water ×2
Rules
When Pokémon-ex has been Knocked Out, your opponent takes 2 Prize cards.
