Gema has short, spiky dark navy hair with a ponytail down the left side. He wears a pair of headphones, circular glasses, a red bandana, and is holding a gaming device. He wears the "Red Armband of Leadership" with a picture of a gaming controller on his left arm.
"When he's not playing video games, talking about video games, writing about video games, reading about video games, trying to develop video games, listening to video game soundtracks, or watching video game streams, then he's probably miserable and wishing that he was playing a video game instead of whatever he's doing. A portable gaming system is almost always in his hands, and he has been caught playing games in class numerous times.
He is completely unable to relate to other people who don't play video games, and has zero interest in conversing about any other topic. His strong desire to find like-minded individuals was what led him to form the Gaming Club. His club application was denied by the school, but he still operates an unofficial club in the Computer Lab anyway. The other students of the school acknowledge his club as a "real club", even if the school faculty does not.
Aside from his passion for gaming, he is also known for being very difficult to get along with. He becomes irritated very easily, is a very sore loser when playing competitive games, and generally has a very poor attitude. His antisocial nature has caused him to experience a lot of teasing and bullying, so he prefers to remain in the school's computer lab during most hours of the day. The few people who have managed to become friends with him have observed that he secretly has a very strong desire for the approval of others."
- YandereDev decided not to include his silhouette in the "Osana Progress Report and Mission Mode Update" video, as he looked as if he was holding something other than a gaming device.
- Gema's name literally means "intransitive" in Japanese.