Which one comes first, Octo Expansion or the normal campaign?

Question

I play Splatoon 2 and the original and was wondering about the question above, which one comes first in the timeline.

Answer 1

The only absolute information regarding the campaigns' timelines is that the second game takes place 2 years after the first.

Within the context of the second game, Hero Mode and Octo Expansion are deliberately kept separate to prevent plot holes if done out of order. That's why the chat logs in Octo Expansion don't feature Callie, as that would only make sense if you've beaten Hero Mode already.

This means that they come in whichever order you do them, as Splatoon canon is fuzzy like that.