Ciphers are personal. A given demon’s Cipher might include one Embed from each category, four from one category, or any other combination. The only way to discover the Cipher is to learn more Embeds and then try them in combination with the ones the demon already knows. When a demon discovers one of these Embeds (called Keys), she undergoes a transcendental, life-altering moment of awareness. This might be blissful, or it could be so shocking that the demon withdraws from all contact with others for a week. In any case, when a demon uses a new Key, she always knows it.
As demons progress, they learn how Embeds work and uncover more about the mystical subroutines put in place by the God-Machine. Some of these subroutines seem familiar or instinctive. These feelings, halfway between déjà vu and enlightenment, can lead a demon to her Keys. These pathways do not come from the God-Machine, though. The God-Machine is not a teacher attempting to help demons on their way, and neither is it trying to lead demons back into its services (though some demons believe exactly that). By investigating her own Keys, a demon is moving further away from the God-Machine on her very own Descent.
The fact that a complete Cipher always involves four Embeds is not lost on the Unchained, and demons often wind up superstitious about geometric and mathematical expressions involving the number. This isn’t always wise — the God-Machine is quite capable of exploiting a demon’s dependence on a pattern or confirmation bias about the number. Realizing this, some demons continue looking for a fifth Key to complete a circuit. Adding a fifth Embed to a Cipher, though, invariably causes it to fail spectacularly and break the demon’s Cover. In some Agencies, demons known for attempting to add a fifth Key are viewed as dangerous instigators.
The final secret of a Cipher is not the endgame or final fate of a character. Rather, it is a technognostic truth, a machine-based koan that teaches the character something about the true nature of reality and the God-Machine. It might be a revelation, a secret bit of code that the God-Machine never intended for anyone to see (or might not ever remember is there). It might be a pathway to lead the character to Hell - or just shift her understanding of Hell. The final secret does not, in itself, allow the character to complete the Descent, but the final secret should confirm or clarify that character’s vision of Hell. The final secret is not necessarily personal to the character. The Agenda — and, of course, the Fall itself— are all external, difficult decisions that a demon makes. The God-Machine doesn’t construct the Ciphers for demons. Indeed, they seem to be nothing more than side effects. Some function of the Infrastructure of the world does not allow an angel to Fall without a Cipher for it to follow. Is that because, to the God-Machine, having a demon following the Cipher is preferably to having more Exiles (who don’t have Ciphers)? Or is it just a side-effect of the ability to Fall — the demon has some magical context in the world? These questions are above the level of most demons to answer. The final secret of a Cipher gives a demon a greater degree of what she wanted in the first place — freedom.