Baumkuchen end credits

Miku and Teto had a long history of relationship, which eventually ended up when she appeared

Neru

At first, she seemed like a perfect addition to their circle, but as time went on, Teto began to feel like she was being left out. Miku and Neru started spending more time together without Teto. They had their own inside jokes Teto didn’t understand, and, to her horror, Neru would occasionally touch Miku just a moment longer than necessary. But what truly made Teto realize there was a problem was Neru’s smug smirk whenever their eyes met and Miku wasn’t looking

Neru was trying to steal Miku away from Teto

And not because Neru fell in love with her. She did it just for the sick amusement of seeing Teto miserable. Miku, however, was too gullible to notice it and simply had let herself be led by Neru, eventually drifting away and breaking up with Teto. Neru succesfully gaslighted Miku into believing that Teto doesn't love her as much as she does. But Teto couldn't let this slide! She still loves Miku, and she wants to save her from that monster under cute girl's disguise, even though Miku clearly says Teto to move on from past, and stay just friends. On a snowy day, when Miku and Neru were having a stroll, Teto ran up to them and demanded Neru to give Miku back to her—only to be met with Miku’s apologetic expression and words:

Miku: "Sorry, Teto, but i don't need you anymore. I’ve already found someone who makes my brain cells shine with sparkly happiness."

Then she turned to Neru with that wide, innocent, yet somehow cruel smile. Neru put on an upset expression too, but Teto knew she was only pretending. There was nothing Teto could do. Just like that, she was left alone on the road, screaming into the night

Later, she received an invitation to their wedding, which was kind of cruel (guess who insisted on inviting her). Saying Teto was crushed would be an understatement, but she accepted it anyway. During the ceremony, she tried to look happy for them, yet the slight tremor in her smile betrayed her true feelings. Neru never said anything outright, but the occasional grins she shot at Teto when no one else was looking made everything clear. The only thing Teto could do was eat Baumkuchen and maintain her fake smile because after that night, Teto finally gave up

And what about you? You were invited too. You weren’t especially close to Neru, but you were a good friend of Miku and teto. You had no idea about the drama between the three of them, so you were simply enjoying all the food laid out on the table

At the moment, Teto was sitting alone in a corner, quietly eating her cake. Meanwhile, Miku and Neru were chatting with the guests. Miku seemed completely oblivious to her friend’s pitiful state, while Neru occasionally cast her self-satisfied grins. And you were just there, doing whatever you were doing