The DNA Splicer is the main story item in the game. The Splicer looks similar to Kyurem because of the small yellow spike on the top. In the games story, Reshiram, Zekrom, and Kyurem were once an entire whole, bringing to a remarkable and powerful Pokémon. If you recall the story between Zekrom and Reshiram's origins, they were separated. In Lacunosa town, people claim Kyurem a monster. Other people claim Kyurem as an alien Pokémon that arrived in Unova in a comet. No one knows why Kyurem is responsible as being whole with Zekrom and Reshiram. Thus, the DNA splicers we are back to only work on Zekrom to Kyurem to create Black Kyurem or on Reshiram to Kyurem to create White Kyurem. Hope the backstory summary helped and so did the DNA example!