After the three Shadows escaped, four temples appeared along the city: Leo Temple, Aquarius Temple, Taurus Temple, and Scorpio Temple. Shadow Tatsuya was at the end of the Leo Temple protecting the crystal skull of said temple. When Tatsuya and the others arrive to where Shadow Tatsuya is, the latter taunts Tatsuya by saying that he knows his dreams (said dreams depends on what the player chooses at the beginning of the game during Saeko Takami's counseling). He tries to trick Tatsuya into admitting that he hates Jun for what he did when he was Joker, depending on the player's choice, the Shadow will make another remark about that Tatsuya must hate Jun, all the trouble he caused to the city and the pain he brought to his friends and him. Whatever the player chooses, the scene will lead to a boss fight against Shadow Tatsuya.
After the battle ends Shadow Tatsuya says that he is impressed on how strong Tatsuya is, but it was obvious since they are the same. He tells him that it doesn't matter if he is defeated, and that he must not forget that he is his Shadow and that he will always be around.
Due to his very straightforward moveset, Shadow Tatsuya is the easiest of the Temple Guardians the player will encounter. It is recommended that before the player enters the battle they equip Tatsuya with his Persona Apollo. If this is done, a special scene will play at the start and end of the battle which will grant Apollo immunity to Dark based spells. The best tactic for defeating Shadow Tatsuya is using the Dashing Strike Fusion Spell (Zio + Tackle); an incredibly powerful attack that deals low Havoc Damage, but hits the enemy multiple times. Tackle can be found Persona like Taranis, Nezha and Cerberus, while Zio is easily found on the Pixie Persona. Have Michel (with his high Strength stat) initiate the Fusion Spell while the rest of the party either attacks or heals.
His only noteworthy attack is his unique Dark Nova Kaiser; which hits a single target for both Almighty and Dark Damage. However, in comparison to Shadow Lisa and Eikichi's unique spells (which hit the entire party), the spell itself is very manageable.
Dark Nova Kaiser! (When he uses the spell Dark Nova Kaiser)
Tatsuya in front of his smiling shadow
Art of Shadow Tatsuya grinning
Shadow Tatsuya alongside Shadow Eikichi and Shadow Lisa at Caracol
Portrait of Shadow Tatsuya grinning from the PSP version of Innocent Sin
It is hinted that Shadow Tatsuya may represent Tatsuya's emptiness and his lack of direction in life (if his response to Ms. Saeko is not having any dreams for the latter). Hints are that Lisa spoke about his Shadow sounding cold and empty as if he's a machine and the Shadow mentioning about dreams and goals being meaningless in one's life and expected life to decide. The Alaya Shrine Incident may have affected his view on dreams which rendered him emotionless.
He's one of the only two Shadow Selves of a protagonist in the whole series, and the only one whose name is player-chosen, due to how the player is able to rename Tatsuya but not Maya.