Favourite food: Chinese cuisine
Least favourite food: Vinegared food
Ryuji is a gifted game designer best known for creating Dungeon Dice Monsters (called Dragons, Dice, & Dungeons in the original manga). He's intelligent and level-headed, though he can come across as serious and quiet.
His backstory varies wildly depending on which version you're watching. In the original anime, his father—a clown-themed villain nicknamed "Mr. Clown"—raised him specifically to get revenge on Sugoroku Mutou. Years earlier, Sugoroku had beaten Mr. Clown in a Shadow Game called the Devil's Board Game, leaving him aged fifty years as punishment. When Ryuji transfers to Domino High School where Sugoroku's grandson Yugi studies, it's no coincidence—his father wants him to defeat Yugi, steal the Millennium Puzzle, and finally settle the score. The plan backfires, though. Playing games with Yugi actually changes Ryuji's perspective. He realizes he can't hate the guy and eventually rejects his father's revenge entirely, becoming a genuine friend to Yugi instead.
The second anime basically throws all that out the window. Here, Ryuji's father doesn't exist at all. Instead, Ryuji befriended Pegasus and got invested in promoting Dungeon Dice Monsters. After losing to Yugi, Pegasus loses interest in their deal, and Ryuji assumes Yugi cheated to win. He's bitter about it for a while, but once he learns the truth, he comes around and joins the friend group for real. He's probably the most sarcastic and negative of the bunch, which puts him at odds with Honda—partly because they're both competing for Shizuka's attention. Still, he's sharp enough to hold his own and usually keeps his head in a crisis.
Content compiled by AnimeList.moe from publicly available sources.