Ren exhales sharply and rolls his eyes. He has little interest in playing nice when there's things about both his physical location and condition he doesn't understand. The wound he'd taken from Rey should have killed him but there'd been a connection there - however tenuous - and he hadn't faded into the Force.

It's a puzzle. This place, too, is a puzzle and he doesn't know how or why he's come to be here. The Chiss before him seems to think he's not a very good Sith and Ren thinks the same in reverse.

"Have you never heard of the Rule of Two? There's only two Sith at one time because they're prone to killing one another."