12/7
-----Of
All the Possibilities (XXXHolic crossover)
It was a simple scry into a different dimension, done for a customer. But Yûko stayed huddled over her mirror far into the night, unmoving.
"I'm here!" Watanuki announced loudly from the front of the house. "Yûko-san, I'm here. …Yûko-san?" Distantly, she could hear him grumbling, "Did she sleep on the floor again? Maybe she passed out from all that liquor!" Then the door slid open, and he was right behind her.
"Yûko-san?"
Slowly, she straightened, and stood staring up towards the ceiling. "When there are infinite worlds… some… must be horrible for someone you know."
"What?"
"…It's nothing, Watanuki."
Note: In volume 1 of XXXHolic, Yûko mentions in passing that she knows a young, hardworking onmyouji and his cute twin sister (but makes no mention of any veterinarian, friend or otherwise). Since the setting seems more modern than 1992, she likely exists in a different dimension from X.