B writes...

What tips Orin off that "Orm" is a clone is that he remembers prison visits that didn't happen, because he was implanted with an approximation of the real Orm's memories after the time he was jailed based on the Light's best guesses. This would have made sense on its own. But in the last episode of the arc, it turns out that the Light had the real Orm's brain all along after he was decapitated and put it in a cloned Arion body. So shouldn't they have had access to the real memories of that time? Why then wouldn't they implant those memories as well? Or at the very least, ask Orm-in-Arion's-body for description of what happened? He'd have been able to tell them that Orin never came to see him.

Or is Orm-Arion a complete fake as well, not Orm's actual brain, even though Vandal addresses him as if he's the real thing in contrast to the clone Orm? Is Vandal just letting him think he has the real Orm's brain? But he seems to remember having been killed, since Vandal asks him if he understands now why it had to happen, and he remembers being "out of control".