Gammon Sakanoue (逆之上ギャモンSakanōe Gyamon) is a freshman student at Root Academy. He is a Solver under the alias Galileo. He is Kaito Daimon's self-proclaimed rival.
AppearanceEditGammon has got red hair and gray eyes, he's tall and is always seen with his leather jacket and pants, giving him a delinquent appearance along with his hairstyle and his way of talking. He also rides a motorcycle.
Gammon solves puzzles for money and is often trying to get ahead of Kaito in order to claim the purported treasures offered by the POG. He also makes money to support himself and his sister, as a famous puzzle writer under the alias of "Chidousetsu" for magazines. He appears to have a crush on Nonoha and even enters a cross-dressing contest to show her his feminine side.
Gammon holds a very competitive rivalry to Kaito. He calls him "Bakaito", a combination of Kaito's name and the Japanese word "baka", meaning idiot as well as freakaito(a combination of freak and Kaito). He and Kaito seem to have quite a few similarities, both of them being hot tempered. Gammon is a top candidate to become a full Phi brain although he is the only one that is yet to a vision of the future. Gammon is a talented Solver and Giver.
Despite his rebellious looks, Gammon cares a lot for his younger sister, Miharu, this being the main reason why he solves puzzles for money. He proved to be a good cook, preparing meals for his sister since she can't.
- Gammon's name comes from the board game Backgammon.