- Started off as close friends that jokingly flirted with each other (mostly with girl in red lyrics), and Shuichi caught feelings somewhere along the way. Kokichi may have fallen sometime prior, but he didn't actually act on anything (covered it up with jokes and such) until he confessed to Shuichi.

- They like hanging out in the library.

- Kokichi is constantly giving Shuichi random little knick-knacks (penguin peddling). These items can range from a cool shiny pebble, to a stolen item from Miu, Kaito, or Maki, to the promise rings that he bought for them after almost three years of dating.

- Shuichi is transmasculine, and Kokichi is genderfluid (this is just a general headcanon I have, not really specific to me and my partner).

- They're both a little obsessed with Billie Eilish.

- Shuichi is very easily flustered. Any time he tries to fluster Kokichi, the lying gremlin quickly turns the tables on him.

- Kokichi often has to help Shuichi get past his social anxiety and at least act like a functional human being that isn't terrified of other people and judgement.

- A motto that they often (somewhat jokingly) live by is "Fake it 'til you make it!"

~ ~ ~

I'll probably add more tomorrow-