Oh, please tell me we're getting a SBaHJ-styled recap.
Uh... no. That's not a question I'd thought to ask.
Based on what Karkat said about the Fourth Wall, I've been assuming that the Hussie character was going to stay non-canonical - and for good reason, too.
The author interludes only work because they're clearly not part of the story. If Hussie turns into a real character, then the nonsense above will bleed into the comic, and we'll just be watching Looney Tunes. Now, I like Looney Tunes, but Looney Tunes couldn't pull off a Descend or a Make Her Pay. It doesn't have the right tone.
In short: a Homestuck where Hussie starts interfering with canonical events is a Homestuck without dramatic stakes. How can it have stakes when the author's in the room, reminding us that this is all fake, actually?
The fact that this is being brought up at all is making me a little worried...
When the time comes, I will interact directly with the events of this narrative. But this moment will be responsibly confined to a passive intervention. [...]
My window of influence, end to end, will be exactly ONE YARD.
...and hearing the explicit statement 'I will interact directly with the events of this narrative' is doing nothing to reassure me.
Maybe I'm not giving Hussie enough credit. He is the one who wrote Karkat's Fourth Wall misgivings, so he's clearly aware of the thin ice he's standing on here. So far, Homestuck's meta shenanigans haven't interfered with the plot, and I'm just going to hope that this state of affairs continues.
I don't know what's up with this 'yard', either - but since it's coming directly from Hussie, I'd be a fool to take it too seriously. Hopefully, it's just some extended joke, and doesn't actually represent Hussie jumping into the story.
So that’s the Tumor. It certainly appears organic, and the tendrils extending from its edges make it look like it's slowly spreading throughout Skaia. Maybe it just keeps growing forever, until it collapses into a star-destroying black hole.
There's also a clear yin-yang theming, which could represent multiple dichotomies - but since we're on the Battlefield, I think it's symbolic of the struggle between Prospit and Derse. This struggle has been 'corrupted' by Jack's interference, and can no longer conclude the way it's supposed to.
The walls also bear the sigils of the Players, which makes me wonder what this chamber was originally for. It's located at the exact center of the session, which seems like it'd be important.
I doubt it's solely intended to house the Tumor. Rose isn't sure whether theirs is unique, but both of her hypotheses imply that it wouldn't exist in a non-doomed session.
Ten hours, eh? That’s significantly more time than I was expecting, especially since the Veil’s timeline is down to less than three.