"Evildoers who threaten to choke our peaceful Sumaru with the shadow of fear! I'll send you to the hell where you belong!"
- Megami Ibunroku Persona: Supporting Character
- Persona 2: Innocent Sin: Supporting Character
Megami Ibunroku Persona
"A lazy member of the Fencing Club who quarrels with Tamaki every day."
Tadashi is introduced as an obnoxious, glasses-wearing kid who attends St. Hermelin. He is simultaneously a love interest and rival of Tamaki Uchida. Tadashi is the son of the local pharmacist.
Persona 2: Innocent Sin
"A useless employee at the Kuzunoha Detective Agency who dreams of hard-boiled exploits. Spoiled son of the Satomi Tadashi owner."
Tadashi Satomi is a bumbling, wannabe private eye and employee of the Kuzunoha Detective Agency. He believes Tamaki's joke that the Izakaya Shiraishi restaurant sells weapons if a secret dish is being ordered and spreads the rumor which is taken advantage by the player to alter the reality in order to allow them gain the weapons against Joker.
Tadashi has stolen a Muses' commercial poster from the street which hides the face of the unnamed third member and sticks it on the wall of the detective office. He deduces that Lisa Silverman is that third member of Muses when he sees Lisa stepping in the detective office and zealously asks her for autograph, causing Tamaki to beat him for a lesson.
In the Aerospace Museum, Tadashi and Tamaki are hired by Maya Okamura to investigate the Masked Circle. They disguise themselves in black outfit and black goggles but their alumnus Yukino Mayuzumi instantly recognizes them as she hears their voices. When King Leo sets fire on the museum, Tadashi and Tamaki guard before the stair to the next floor until the player has found all the child visitors of that level. When all children are retrieved, Tadashi at the rooftop dashes towards King Leo for an attack but is comically defeated.
Later, after Maya Okamura gets kidnapped, Tadashi states that a job as a detective might not be for him and that he is considering a career as a game designer instead.
Persona 2: Eternal Punishment
He does not appear at all in Eternal Punishment, having apparently been chased off by assassins shortly before the start of the game.
- The name Tadashi means "straight, direct" (直).
- Tadashi's surname Satomi means "village" (里) (sato) and "see, hopes, chances, idea, opinion, look at, visible" (見) (mi).
- In Innocent Sin, Tadashi's disguise during the mission in the Aerospace Museum alludes to the fictional hero Zorro.
- Tadashi being scrapped from Eternal Punishment is the result of fans' complaints that the writer used the series to express his personal admiration for the female idol Yuki Uchida, whom Tamaki Uchida is modeled after.