I see. It's rare to have a bond like that.

[ Kaiba felt a slight pang here. He'd never had a pet, of course, but Wormmon was more than a pet, wasn't he? He was a beloved friend, almost like a brother...

He briefly squeezed the locket hanging from his neck. ]

Is there any way I can help you? I don't know anything about your world and how it works, but I've done some research on dimensional travel.