Hob might not need to keep his immortality a secret here, but even if he did, he’s certain that Loki would keep his secret. "I know I can trust you." Maybe Dream would not agree with how quickly Hob has come to trust in Loki, but Hob just gets the sense that he can, and he's generally a very good judge of character.

"It used to be easier. Reinventing myself. The more the world evolves, the harder it becomes. I fear my secret may not be a secret forever and then..." Well, who knows what might happen to him. Maybe there's no avoiding being someone's specimen someday, or the target of some dark magic user who wants immortality for themselves.

"Gods are immortal, aren't they? And live with other gods? That must be nice."