Opal realized that she hadn’t closely examined the elf since she’d appeared at the crater’s rim. Either she’d been lying down, or Artemis had shielded her body with his own.
But her face. I saw the face. It was definitely her.
The second thing to happen was that the small hand in question, which still rested on the Berserker Gate, began to crab spasmodically toward the handprint, feeling its way with fingertips.
Opal pulled back Holly’s hood to take a better look and saw that the face crackled a little on close inspection.
A mask. A child’s projection mask. Like the one used by Pip…
“No!” she screamed. “No, I will not permit it!”
She reached under Holly’s chin and wrenched off the mask, and of course it was not Holly underneath.
Opal saw her own cloned face beneath the mask, and she felt instantly traumatized, as though blindsided by a massive blow.
“It is me!” she breathed, then giggled hysterically. “And only I can close the gate.”
Two seconds of stunned inaction followed from Opal, which allowed Nopal’s fingers to arrange themselves perfectly in the handprint. The print turned green and radiated a warm light. The smell of summer emanated from the stone, and there was birdsong.
Artemis chuckled, showing his blood-rimmed teeth. “I would imagine that you’re vexed now.”

The Last Guardian, Chapter 18