While the player does not have a Black Kyurem or White Kyurem, the DNA Splicers can be used to fuse Kyurem with Reshiram or Zekrom to become White Kyurem or Black Kyurem, respectively.
While the player has a Black Kyurem or White Kyurem, the DNA Splicers can be used to separate White Kyurem or Black Kyurem into Kyurem and the original Reshiram or Zekrom. All properties of the Reshiram or Zekrom will be retained.
The DNA Splicers can only fuse together one Kyurem and Reshiram or Zekrom at a time. In order to fuse a Kyurem with a different Reshiram or Zekrom, any existing fusion must be undone.
The DNA Splicers first appeared in The Frozen World, where they were revealed to be in Drayden's possession. In order to obtain the item for their plans, Team Plasma attacked Opelucid City while Colress used the Plasma Frigate to freeze the entire city, allowing Zinzolin to steal the DNA Splicers from Drayden.
The DNA Splicers first appeared in Abyssal Ruins, where Blake revealed that he had possessed them ever since he was a little child, not knowing how he got them. After Colress managed to make Zinzolin spill out his information regarding Kyurem's Absofusion, he relayed this information to Ghetsis, who had Kyurem call out to the DNA Splicers, causing them and Blake, who was trying to hold on to them, to fly up towards Kyurem. The item's energy eventually repelled Blake from it, and once Ghetsis ordered Kyurem to absorb N's Zekrom, Kyurem absorbed the DNA Splicers and forced Zekrom to turn into the Dark Stone, which it used to transform itself into Black Kyurem.
