Teddie's History
*Spoilers for Persona 4 *
Teddie serves as the guide for the Investigation Team in the Midnight Channel. At first, he acts as support for battles, but after the party completes the Marukyu Striptease dungeon, he joins in combat, while Rise takes over the support role. Whenever a new team member joins, Teddie is inexplicably able to create glasses so that they can see through the fog in the Midnight Channel.
Teddie was first seen in the Midnight Channel at the time when the protagonist, Yosuke Hanamura and Chie Satonaka search for an exit, after leaving the Desolate Bedroom. Teddie, confused and irritated by their presence, asks them to leave because it's dangerous there and shows them the exit. After Saki Konishi's death, the protagonist and Yosuke enter the TV again in order to investigate. There, they meet Teddie once again, but he gets suspicious and thinks that they are the ones who've been throwing people in. After they try to prove their innocence, Teddie asks them to find the real culprit and makes them promise to do so in order to let them out. When the protagonist first awakens to his Persona, amazed by his power, Teddie immediately calls him "Sensei." He assumes the support role for the team until Rise joins the party.
After Teddie defeats Rise's shadow, his own Shadow appears as a larger form of his bear costume, coming out of a hole in the ground. Unlike most of the other Shadow selves, Teddie's Shadow is highly intelligent, speaks in a deep and intimidating voice and does not wait for Teddie to deny him before attacking the party, mocking the Investigation Team's goals of seeking the truth as a waste of effort. However, this may be due to the intervention of another party, as Rise stated she felt the intervention of a powerful presence, most likely Izanami or Ameno-sagiri. It represents Teddie's hiding the truth about his identity, that is, the fact that he is a lost, lonely Shadow. He learned to speak human language and became friendly with humans, taking his bear-like form so that people would like him upon meeting him. Teddie eventually grows a human body so that he can be with other humans. After gaining a personality and losing his Shadow mask, he receives his own Persona. When the team was about to leave after the successful rescue of Rise and the defeat of his shadow, Teddie decides that he wants to be alone for a while and train in order for his fur to grow back and to be stronger.
Right after the death of Kinshiro Morooka, the team asks Teddie, who has come to their side, if someone was thrown in the TV while he was in, but Teddie answers negatively. The ultimate surprise comes when Teddie complains about the heat and tries to remove his bear suit, much to Yosuke's disapproval, because he thought that Teddie was going to be empty inside, but he was not: Teddie had grown a human body while training. Teddie then becomes a front-line ally, giving the support work to Rise. His Persona is Kintoki-Douji of the Star Arcana.
When Nanako "dies," Teddie is so devastated and consumed by his own powerlessness of being unable to keep his promise to Nanako, that he feels he lost his reason to live in Inaba. Teddie then disappears and becomes immersed in a world of fog in his bear form, because Shadows are not allowed in the real world, and his human identity, which allows him to leave the Midnight Channel, has faded.
In the game's bad endings where the protagonist is unable to continue solving the mystery, the protagonist finds a farewell letter from Teddie who mentions that he has returned to the Midnight Channel but expresses his gratitude for the time he has spent in the human world with the Investigation Team.
"The purpose of this room is to nurture egos. Shadows, mere fragments of the Ego, have no place here. Very interesting."
—Igor, on Teddie's appearance in the Velvet Room.
If the protagonist is able to continue solving the mystery, then on December 5th, Teddie appears in the Velvet Room with the usual occupants nowhere to be seen. He explains the origins of his existence to the protagonist, and is saddened to realize that he is merely a Shadow who took the form of a cartoon bear so that humans would like him. Teddie asks the protagonist to apologize to Nanako in Heaven. However, when the protagonist reveals to Teddie that Nanako never died, Teddie regains his strength. After Teddie leaves the velvet room, Igor, Margaret, and Marie (in Golden) appear, with Igor mentioning how Teddie's appearance is "very interesting," because Shadows should not be in the Velvet Room, with him having "a meaningful smile on his face."
The next day, Teddie returns to the Investigation Team with newfound vigor. After the events of the game, Teddie lives with Yousuke.