If gaming pulls some evil out of you, and you like to show cards to your opponent and then make them discard those cards, then you can put these to good use: Razorkin Needlehead, Smothering Tithe, and Fate Unraveler
This dramatic depiction ties directly to Volcanions Pokdex lore, which describes it as being able to create explosive steam by releasing superheated water stored within its body
Ezuri, Renegade Leader Ezuri, Renegade Leader was the best payoff for playing elves for a long time in formats like Modern
Aside from one exception in the Sword & Shield era of the Pokemon TCG (Dark Sylveon V, to be exact), the most recent Dark Pokemon cards at the time of writing are from the early 2000s with the EX Team Rocket Returns expansion set
Me: Official answer: Seven just felt right