Gaoyu did remember the plot of one of the movies.
In it, Rukia adopted two children in Rukongai. Later, they encountered a "Parasitic Hollow" that possessed the two children and eventually merged with Rukia.
When Rukia, the two children from Soul Society, and the Parasitic Hollow fused together, Dark Rukia was born.
If her eyes were a little more purple and a little darker, she'd look even more like her.
But...
The movie should have taken place in a parallel world. Just as this world had no Kusaka Sōjirō, the two children Rukia adopted shouldn't exist either, let alone Dark Rukia.
But...
What was happening to Rukia right now?
"She looks..."
Gaoyu hesitated for a moment before saying, "Pretty cool, actually."
"Who would've thought a Shinigami, the Hogyoku, and White would fuse and cause a change like this? Don't you think it's... interesting?" Aizen said softly.
"It is pretty interesting. Honestly, I think Rukia only really looks like a Shinigami when she's holding a scythe like that."
Gaoyu teased him, then sat down in the chair in front of Aizen's desk. He asked, "How did Rukia end up like this?"
"That's something you'll have to find out for yourself."
Looking at Aizen, Gaoyu knew he had to understand what was going on, but simply didn't want to tell him.
He asked again, "Does the Kuchiki Family know about this?"
"No."
"Why not?"
"Even Kuchiki Rukia herself doesn't know."
Aizen spoke mysteriously. Seeing that he wouldn't get any useful information out of him, Gaoyu pursed his lips and prepared to leave.
But before he could go, Aizen suddenly asked, "Do you want the Hollows in Las Noches to undergo Hollowfication?"
"Since we already have Arrancar, why not expand their numbers?" Gaoyu said. "Otherwise, dealing with ugly things every day is going