The Lost Characters

The Lost Characters is the fan name given to characters that were created in the Twitch Plays Emerald stream before A, but deleted due to soft resets.

Slash
Slash (/') was the first of the Lost Characters. Her name may have given rise to the idea of A (or Slash herself, as a fractured personality within A's psychosis) as a homicidal psychopath. She is easily the most hostile of the personalities in the "A has DID" interpretation of the lore (see below).

Camila
Camila is the least-expanded on of the Lost Characters. She is occasionally portrayed as one of A's secondary personalities, and is the least hostile of the three, sometimes being depicted as nurturing and protective.

T
T was the only male of the four characters created for Gen 3. He has been, for most participants, considered a composite character with Brendan.

The Fate of the Lost Characters in Lore
There are two major interpretations as to what became of the Lost Characters. The first paints them as victims of A's pre-game crimes, murders she committed prior to arriving in Hoenn and beginning her adventure. Some theorize that their deaths were required to perform the ritual that summoned The Voices.

The other theory is that A suffers from Dissociative Identity Disorder, and that Slash and Camila are two secondary personalities of hers. Slash is a psychopath, sadist, and murderer, while Camila is more gentle and protective, and A's default personality is the happy-go-lucky, adventuresome anarchist. While the primary personality of most usual victims of DID is not aware of the secondary personalities, A appears to be an exception, shown as freely conversing and arguing with Slash and Camila. It is unknown whether her alliance with the Voices was A's work, Slash's, or a collaboration between the two.

In both theories, T is generally identified as Brendan, the only survivor of A's or Slash's pre-game murder spree. Some extensions of the lore detail T having saved before one of the soft resets wiped him out completely.