Gideon (Japanese: スミオ Sumio) is the head Team Rocket scientist at the Team Rocket's Sevii Islands branch (and possibly the entire Team Rocket) in Pokémon FireRed and LeafGreen.
The first possible sighting of Gideon happens if the player attempts to enter the Dotted Hole prior to defeating the Team Rocket Grunts in the Icefall Cave. Gideon will be seen blocking the entrance, pondering how to get in.
After the player arrives in the chamber of the Dotted Hole that contains the Sapphire, and attempts to get it, Gideon falls through the hole of the floor above, and grabs the Sapphire. Before he leaves, he tells the player the second password to the Rocket Warehouse in Five Isle Meadow. Infiltrating the said warehouse is the only way to get it back and thus making it possible to trade with the Generation III Hoenn-based games. After battling through a pair of Team Rocket Admins, the player must battle Gideon, who was trying to sell the Sapphire over the Internet. After defeating Gideon, he angrily hands over the Sapphire. Gideon remains in the warehouse forever, even after Team Rocket has abandoned it, presumably thinking of another get-rich-quick scheme or else doing research of some sort.
Notably, once the player leaves the warehouse and returns after delivering the Sapphire to Celio, Gideon comments to the player that Giovanni has a child with red hair. Through further revelations in Pokémon HeartGold and SoulSilver, it is shown that this red-haired son is in fact the rival of the player in the Johto-based games, Silver.
- Gideon is the only in-game Trainer in FireRed and LeafGreen to use a Porygon.
- Gideon is the only known Team Rocket scientist working in the Sevii Islands branch of Team Rocket.