Gemini appear when a Spectre attains the Orphan-Grinder status, splitting off from the Orphan-Grinder much as a Doppelganger splits from a Spirit when they are first formed. However, there are a few key differences between Doppelgangers and Gemini. First, Gemini have a completely independent mindset from their "good" counterparts; they develop their own abilities independently of the Orphan-Grinder. They may use any of the standard, non-Orphan-Grinder Horrors they knew before they merged to form a Spectre, but cannot learn new ones unless they are Spectral Horrors.
Drastically different from Doppelgangers, however, is the purpose of a Gemini. A Gemini has no knowledge of it or its counterparts former life, and therefore does not act with malice towards the things that remain in the life of the Orphan-Grinder. Instead, the Gemini exists for one reason: to return the Orphan-Grinder to Spectredom. In this, the Gemini are relentless and merciless; any Orphan-Grinder, not just their original counterpart, will do. Their usual means are attempts to steal Willpower, but they can be as creative as other Spectres in creating traps for an unwary Orphan-Grinder.
Geminis, like Doppelgangers, will eventually reform if destroyed. However, if an Orphan-Grinder succeeds in redemption by ridding themselves of all Spite, the Gemini will disentigrate. Everytime an Orphan-Grinder succeeds in getting rid of Spite, the Gemini will redouble their efforts to stay in existence. If an Orphan-Grinder fails, however, and returns to being a Spectre, the Gemini again merges with them to form a special kind of Spectre, the Lawgiver.