Kyurem

Kyurem, the Boundary Pokémon, is a legendary Dragon/Ice-type Pokémon introduced in Generation V. It is unique among legendary Pokémon for its ability to fuse with Reshiram or Zekrom, forming White Kyurem or Black Kyurem, respectively, a concept central to the narrative of Pokémon Black 2 and White 2. Kyurem's natural habitat is the Giant Chasm, a desolate and frigid crater, reflecting its icy nature. Its diet, if it has one, is never explicitly stated, but its existence is tied to the original Dragon that split into Reshiram and Zekrom. Behaviorally, Kyurem is often depicted as a fearsome and powerful creature, capable of freezing anything around it. In the games, it is often sought after for its immense power and its role in the Unova region's history. In the anime, Kyurem plays a significant role in "Kyurem VS. The Sword of Justice," showcasing its formidable abilities and connection to the legendaries Cobalion, Terrakion, and Virizion. Its unique fusion mechanic and imposing design have cemented its place as a fan favorite and a culturally significant Pokémon, representing the remnants of a greater power.