aka The Red King? Per Sinister Secret #12:
" ...the changing of the tides at the Hellfire Club Bay. We hear one of the seas to be carefully navigated is deep and red."
Namor was shown to be hostile toward the hellfire club back in Fraction run. However, if he was joining the club at this time, it would be a "changing of the tide", would it not? It would make sense that a sea-trading division of Hellfire club have Namor on its back, hence "...one of the seas to be carefully navigated is deep and red." Obviously, this would mean Namor is the Red King, per the red reference. Deep could reference to Namor and Emma "deep" history with each other.
Moreover, did you notice that Namor was quite heavily featured in HOX 6? Hickman would not show him off in such a manner if Namor did not have major roles in Krakoa's future/