Diancie did not know every detail of Yveltal's abilities, but it was like a player on their second playthrough, clearly aware of most of Yveltal's methods.
The dazzlingly golden Diancie did not use Photon Geyser, which was especially convenient within the Radiant Aura. In Yveltal's state of primordial evil, its immunity to Psychic-type attacks was so strong that it was practically taking no damage at all...
Even if Diancie used Photon Geyser now, it would be completely neutralized by the dense primordial dark aura surrounding Yveltal.
However, Diancie had never intended to rely on Photon Geyser in battle.
Most of the immense power gathered by Xerneas's Earth Power, along with the strengthening effects of the Fairy Aura, had been poured into Diancie.
At this moment, it could be said to be fighting while wielding half of the Fairy source!
Facing the Dark-type version of Oblivion Wing fired by Yveltal, suffused with dense Dark Energy, mixed with only a trace of Flying-type energy, and enhanced by Dark Aura—
Diancie raised the tip of its scepter toward the sky. In an instant, the heavy, low-hanging clouds overhead seemed to disperse, revealing a brilliant starry sky.
Cosmic Power gathered at the tip of Diancie's scepter, overflowing across its surface.
The next moment, like a meteor streaking across the night sky, a dazzling Meteor Beam shot forth and collided violently with Oblivion Wing.
Although Diancie had used a Rock-type Move, the power it had drawn upon still came from the halo behind it, inevitably carrying a trace of Fairy Energy.
With the help of that Fairy Energy, Meteor Beam tore through Oblivion Wing like a hot knife through butter and slammed heavily into the dense black aura covering Yveltal's chest!
Sizzle, sizzle, sizzle—
Intense scorching sounds rang out continuously. Just like the externalized energy