I saw a prompt on BadBadBathhouse asking for Minato or Minako to return from the Great Seal, bonus points for it being Theo or Elizabeth's fault, and the IT rushing to save Seta before time ran out, but pfft, I can't make anything easy for them though...well not Yosuke. Yosuke is a special case to me. I went 'Minako' route with this, so I could make Yosuke have a difficult time deciding.
Back Story: Yosuke and the FeMC were cousins, after her parents died, the third person she lived with was the Hanamura household, who moved around a lot. Her and Yosuke became as close as Souji and Nanako, and when she was 17, she passed away, leaving Yosuke devistated. He met Souji Seta 14 months later and by the time of the final battle, Souji and Yosuke were in an intimate relationship.
She sat up and blinked once. Twice. Three times. The last thing she remembered was falling asleep in Shinjiro-senpai's lap. This was her room in her aunt and Uncle's house, she knew that much, but her little objects, the Pig keychain from Junpei, Aigis' charred screw, her watch from Shinjiro, Akihiko's knit rabbit, Mitsuru's Motorcycle key, Ken's house Key, Koromaru's collar, Fukka's headphones and Yukari's choker. Various other objects sat on the shelves, and her Evoker sat on the table. Her name and S.E.E.S engraved into the metal. Everything looked so well taken care of.
"YOSUKE!" An unfamiliar voice shouted and she stood up, heading to the door.
"Ted! Shut up! I'm on the phone!"
"With Nana-chan! I wanna talk to her!"
"TED GET OFF ME!" She slipped out of the room and headed for the one where the voices came from. This wasn't the house she remembered. She watched her cousin, he had to be at least 17 now, kick some poor unfortunate soul out of his room.
The person, short, blond hair, blue eyes, wearing a white shirt and jeans, looked up and saw her.
"Oh wow! You're beary pretty~ How did you get in here though?"
"I woke up in that room."
"Oh wow! Yosuke won't let me go in there! He said it's for a beary special person to him!"
"I'm Rai Shadow. Yosuke's cousin."
"Teddie. I'm living here with Yosuke. He's on the phone with Nana-chan though and he sounded upset."
"Ted!" Yosuke ran out into the hall, hitting the wall across from his room. "It's Partner! Nana-chan said he isn't waking up!"
"That's beary bad news! Oh and Yosuke, this is Rai-chan! She woke up in that room you won't let me into! That's not fair, right Yosuke? Right?"
Yosuke took one look at the girl and passed out.
Edit: Added Teddie saying something other than "!"