Numerous FAQs on the internet have the wrong information for recruiting, in my opinion, the best of the secret characters in SMT: Persona – Reiji. If you’re interested in getting him in to your party, prepare for a little bit of traveling around the map and going through some hard times with only four characters, but the end result is definitely worth it!
You want to start working on this as soon as the game starts and you have control of your protagonist in the infirmary.
Step out of the infirmary and head north passed the exit, stepping in to the first room which is the Teacher’s Lounge. Talk to the teacher in the brown suit and he’ll mention someone going in and out of a room on the second floor.
Head upstairs and take the hallway passed room 2-6 and in to the door of the next room on the right (it won’t be marked like the others). A short scene will play out with Reiji before he leaves. This is where many FAQs give incorrect information, pointing players toward room 2-4 which leads to a scene of a girl asking you to return a book to Maki in the hospital. If this is the room you are in, you are in the wrong hallway. The correct hallway starts with room 2-5, then 2-6 and then a final un-marked room which is the one you’re looking for.
Leave the room and head to room 2-1, talking to the boy standing next to Mark. He’ll mention something about wanting abandoned buildings demolished because they draw in hooligans.
Exit the school completely and going up one map, then right one map until you see a cross shaped building called Joy Street. Head inside and the first door on your right should lead to Judgement 1999, a casino. Go inside and talk to another boy standing next to Mark (there are two, so make sure you’ve talked to the correct one) who mentions a boy headed to the Abandoned Building with a scar on his forehead. That’s Reiji!
Head out of Joy Street and go to the southeastern most map, entering the Abandoned Factory for another short scene with Reiji.
Make your way back up and enter Joy Street once more. Inside, look for the Yin & Yan door, enter and talk to the woman in the yellow shirt. She will ask you two questions and you must answer the first with “Yeah” and the second with “Sure“.
At this point you’ll need to head to the hospital to advance the story, but as soon as you leave the hospital you must immediately head south to the SEBEC building, entering the SEBEC Blockade (the red arrows on the map near the SEBEC building) for a quick scene with Reiji fighting with some guards. Mark will break it up and Reiji will leave once more.
There is one more step to recruiting Reiji but you must play the game from this point forward without allowing any of the other students to join your party. When you free Mark from the Police Station, make sure you decline Brown’s offer to join, as with Elly in the Subway, etc. This is crucial. If you missed any step, one of the other students will most likely force their way in to your group. Once you head back to the demonic version of St. Hermelin, in the fourth zone Reiji will show up and join your party. Ta dah!
I hope this helps! I hadn’t played the original Persona since it was Revelations on the PSX in the late 1990’s, so when I started playing the remake on PSP I couldn’t remember how to recruit him (I think his name was Chris in the original and Mark was actually converted in to a black guy?). If I missed anything, let me know!