'Go back to the Tomb of Ariel...'
Technically, that was an erroneous statement.
Sunny had never been inside the Tomb of Ariel, after all. Neither had anyone else — no human of the War Realm, that was. Asterion had attempted to reach the Great Pyramid once, but failed to overcome the Nightmare Desert and was forced to turn back.
What Sunny had visited and endured was the phantom version of the Tomb of Ariel conjured by the Spell. It was easy to confuse the two, at times, but the distinction was important.
So, it wouldn't be correct to say that Cassie had sent a message telling him to go back to the Tomb of Ariel. Rather, she was telling him to enter the real Tomb of Ariel, for the first time.
'No wonder…'
No wonder the Chain Breaker had been drifting in the Great River. No wonder that, unlike the other members of the cohort, Sunny and Nephis had taken the roles of themselves in the Nightmare, as opposed to the roles of local heroes.
