Oh.

Wayward Vagabond didn’t have any revealed name other than “The Mayor”, and he governed over real people.

I thought that that trolls turn into the animal their lusus when fully grown

This doesn't entirely count since I've been reading Homestuck since Day 1, but when Act 1 ended I thought John was dead, his meteor ruined civilization, and the story would follow Rose as the protag in a post-apocalyptic world trying to stop Sburb from finishing the job.

before I read homestuck every one kept describing it as "a game that a boy and his friends play" so I thought that the trolls where the characters that the beta kids played as and that Karkat was John game character.

Before I read Homestuck, I thought Eridan was a vampire.

Before I read homestuck I thought the Condesce was feferi turned evil.

before i read homestuck i thought sprites were all the dead people’s ghosts and that combined sprites are the dead people who married