There have been several claims of extra characters available in the Prerelease. None is true. There is no functioning eighth character slot. Though Game Genie or PAR codes can manipulate the game into simulating one, it's simply pulling data from nowhere. Rumorists have also alleged that extra frames exist for certain characters (such as running animations). There are none to be found, even for Schala. View this comparison:
No NPC could be used as a playable character anyhow, as their graphics are compressed. Any game that requires lots readily-available graphics that need to be animated quickly cannot have these graphics compressed, or the game suffers severe lag as the CPU must decompress the graphics on the fly. This is why the sprite sets for Crono, Marle, Lucca, and the rest of the PCs are stored raw in the ROM. Schala, Toma, and Gaspar's graphics, however, are compressed and therefore wouldn't be suitable as a playable character.
Gaspar was at one time intended to be the eighth playable character of Chrono Trigger. This plan was likely cut before the Chrono Trigger Prerelease was issued, as no extra sprites for him appear in the ROM. Toriyama's sketch demonstrates that Gaspar would have worn his Zeal robes and carried his staff in the party. The sketch, and his comment of proof, appear in the Chrono Trigger V-Jump Player's Guide.
The Overworld NPC
There is a strange sprite in the overworld sprite data.
It looks like a guard. JLukas analyzed this sprite and found that the game pulls it from NPC data, meaning it probably was a guard meant to block off a location. Apparently, the developers found a way to do it with landscape and scrapped the guard while implementing idle player character animations. Some may argue that this guard looks like the one from Final Fantasy 6, and that Chrono Trigger was built off that game's engine. However, the coding of each game is irreconciliably different.
Cyrus had a different standing pose.
Home Area: Gobb's house
"Gobb" is a character who has his own house. Unfortunately, the house, and apparently Gobb, were both taken out of the game before its final release. He may have simply been a Mystic who owned a house also taken out of the final release; see Medina Residence (CTP). Gobb also may simply be one of the helpful Imps who live in the house which contains a Gate in the cabinet.
Lavos's eruption sprite is different.
Modern Little Girl
These objects aren't in the final or are different.
- Chains (NPC #9D)
- Washpan (NPC #6D)
- Trophy (NPC #66)
- Zeal Teleporter
ワシがこのメディーナ村の村長、 ビネガー13世じゃ！ ワシの先祖は、あのいだいなる魔王様の 一の部下として人間どもと戦ったのだぞ。 ああ、魔王様…… なぜ400年前に 人間達をほろぼして下さらなかったのじゃ？[END]
In the Prerelease, he was known as Ozzie XIII instead of Ozzie VIII.
This is the normal Prehistoric Child sprite with a palette swap.