Tropes for "The Imperishable Night Incident, Part 1" include:
Adaptation Distillation: The story focuses primarily on the Border Team and Magic team, with Remilia, Sakuya, Youmu, and Yuyuko only making cameos.
Adapted Out: Keine's battle doesn't happen in this version of the tale, even though she shows up.
Enchanted Forest: Alice mentions that according to legend, if you get lost in the Bamboo Forest of the Lost, you'll never come out.
Enemy Mine: Reimu and Yukari team up to solve the Imperishable Night incident despite being enemies.
How Did You Know? I Didn't: Marisa ends up revealing Eientei completely by accident when she hits it with her Master Spark while trying to hit Reimu.
Let's You and Him Fight: Reimu and Marisa end up fighting because Reimu isn't honest about why she's working with Yukari, leading Marisa to believe that they're responsible for the incident, and Yukari decides to let Marisa believe that.
