It's not necessary, but iirc, it's mandated to clear it so you can play Traum (cmiiw). Not to mention you still get quite rewards for clearing Tunguska (including up to 50 million QP for completing final battle), so it's better to clear it.

@Muhammad Abdul Aziz Habibi I actually was able to play Traum without having completed Tunguska. I’ll still finish Tunguska though, thank you.

Well, if you're curious on who Koyanskaya actually is and want to see a, very fulfilling, conclusion to her story arc, I recommend reading it.

I think the story leading up to the finale of the chapter was rather boring, if you don't care much for either Ibuki or Dobrynya, but the fights are kinda cool.

Well, it's probably a different beast 😉, if you read the story at once instead of only a couple of storybits each day, followed by raid battles.

Reading only a little every day instead of in one go doesn't make it less shit, at most slightly more bearable.

I spent 3 hours straight completing it's Main Interlude the day it came out... (×﹏×)