Battle Styles is a set in the Sword & Shield series. It was released on March 19, 2021. The printed size is 163. This checklist is longer, at 183 cards. Houndoom is 96/163, in position 96 of 183 on this checklist. Before it is 95 Houndour, and after it is 97 Tyranitar V. The listed rarity is Rare Holo.
Houndoom is a Stage 1 Single Strike Darkness Pokémon with 130 HP. In the Pokédex this is Houndoom (#229), generation 2 (Johto). The card says it evolves from Houndour. In this catalog that name is Houndour (#228).
Ryota Murayama illustrated this card. The same name is on 55 other cards in the catalog.
Houndoom (#229) has 44 other cards in the catalog. Those other cards are in 30 sets. The other printings with a release date run from 2001 to 2025. The earliest other card is Houndoom 4/75 in Neo Discovery (2001). That card lists 70 HP, and this one lists 130 HP. Both list the rarity Rare Holo. Shin-ichi Yoshida illustrated that card, and Ryota Murayama illustrated this one. Retreat cost there is 1, and here it is 2. 38 other cards of Houndoom list a different HP.
Single Strike Roar is listed as Ability. Once during your turn, you may search your deck for a Single Strike Energy card and attach it to 1 of your Single Strike Pokémon. Then, shuffle your deck. If you attached Energy to a Pokémon in this way, put 2 damage counters on that Pokémon. The attack Darkness Fang lists 50 damage. The cost is Darkness, Colorless. Weakness is Grass ×2. Retreat cost is 2. The flavor text reads "Identifiable by its eerie howls, people a long time ago thought it was the grim reaper and feared it." The regulation mark is E.
I keep a set binder for Battle Styles, meant to hold every card of that set. This card is one slot in the Battle Styles set binder. A generation binder holds one card of each species. Houndoom can fill a slot in Generation 2 binder (Johto). I still need this card.