>>37627986But IS headcanon:
"Let me tell you the story. It's a long story, but listen closely. It was two years ago when the two dragon Pokémon were awakened. The black dragon Pokémon, Zekrom, pursued what is ideal,B2/ The white dragon Pokémon, Reshiram, sought what is true,W2 with the desire to usher in a new world of hopeB2/goodnessW2. And the white dragon Pokémon, Reshiram, sought what is true,B2/And the black dragon Pokémon, Zekrom, pursued what is ideal,W2 with the desire to usher in a new world of goodnessB2/hopeW2. ZekromB2/ReshiramW2 and ReshiramB2/ZekromW2 were once a single Pokémon."
"You may wonder why it split in two. The single dragon Pokémon had helped the twin heroes bring a new region into being. But the twin heroes--the olderB2/youngerW2 brother who sought the truthB2/idealsW2 and the youngerB2/olderW2 brother who sought idealsB2/the truthW2--sundered the region in two as they fought to see which of them was right. In that desperate hour, the single dragon Pokémon split its body into a blackB2/whiteW2 Pokémon and a whiteB2/blackW2 Pokémon, even though ideals and truth don't need to be in opposition!"
"As the story goes, a third dragon Pokémon, Kyurem, also came into existence in that era. And there may be proof of this to be found in a treasure passed down in my family for generations: the DNA Splicers. Professor Juniper's research determined that the materials in the splicers date back to the same era as the materials used in building the Dragonspiral Tower."
"Oh, the DNA Splicers are stored very safely. I guard them because I don't know what kind of power might lie within them. But here's what's been bothering me… Could there be one more dragon Pokémon? Even if Kyurem really exists, we don't know what kind of Pokémon it is. For starters, the two Pokémon the ancient Pokémon split into are both overwhelmingly powerful. So if Kyurem exists, could it be just a husk--a shell that was left over?"
~Drayden