Black Bolt did not know who else he could trust.
Lockjaw counted as one. After all, it was his pet and companion, and the most trustworthy member of the Attilan Royal Family.
Perhaps Gordon from Afterlife, the Inhuman settlement on Earth, could be counted as well. The desire for revenge squeezed from his very bones burned through his body. So long as the King of Attilan decided to oppose humanity, Gordon would offer his loyalty. After all, not everyone had the resolve to stake everything on squeezing into a cramped survival pod in orbit, enduring the steadily approaching hunger, suffocation, and cold, all to seek the near-mythical Attilan.
Perhaps Crystal could be counted too. She had nothing to do with any of the royal family's power. She was so innocent and lovable that no one wished to tell her about the worst parts of this world. Let her go on believing the world was made of candy. Let her go on believing goods grew from store shelves. A little princess so innocent she was somewhat foolish suited everyone's interests.
Perhaps the royal courts of the Ghost Clan, Centaur Clan, and Rogue Clan could be trusted. Yet they had never exposed the true state of the lower production decks. Perhaps they assumed the Attilan Royal Family knew the truth, believing Black Bolt already understood the relationship between the upper and lower decks. As part of a political compromise, the Bird People Clan, which controlled the faster-than-light engines, had never involved itself in the work of the lower production decks, instead relying on supplies provided by the other clans. Therefore, the Bird People Clan's ambassador to the Gene Council was also trustworthy.
As for the captain of the royal guard, Black Bolt temporarily placed him on the list of those he could