Hiya, just read that Grimoire card and got to googling to see if anyone else had picked up on it. The Hidden are Ikora's group of Guardians that investigate (and handle) private matters that the Vanguard and Speaker don't always need to know about. Think of them as the City's CIA. Eris has been apart of the Hidden since she escaped from the Moon. Even though both the Speaker and Zavala don't trust her, Ikora vouched for her. Once Oryx showed up in the solar system, the rest of the Vanguard realized she wasn't THAT crazy. The interesting part is that she says "our number within the Hidden." Osiris's cult, or maybe just collaborators, have infiltrated the most secret task force in the Vanguard/City. If it is an undisclosed report, I can't say for certain if Ikora knows or doesn't. Interesting and not threatening, because clearly Eris is fighting for the preservation of humanity. I suspect the orb she is referring to is the one she through on the desk during the Vanguard's initial meeting about Oryx (the one Cayde walked out on). Remember, she used to hold it in The Dark Below. I believe it has something to do with Crota's essence, and has some connection to Oryx. That's why she mentions the "shrine:" that mission in Vanilla Destiny when we took out that big spinning orb that was the original mention of Oryx. That must also be what Crota used to deliver his tribute to his father.