I'm sorry, folks, I had to downvote, though I was reluctant to because of the sheer amount of effort that obviously went into this one from multiple people.
And that, I think, is part of the problem with this and a few other articles I've read of late: a fairly basic premise padded out by huge logs, cool art, supplementary materials etc etc, so that the quantity of added content, rather than its quality, almost seems to be the driver of upvotes.
Not that the quality is all bad here - the art is very nice and the additional historical record neat. But, still, this sort of reads like a My First SCP Idea (big mechanical animal what fites batels) that's been polished up with awesome pictures and added historical info. Which might have been enough for an upvote, still, if the whole thing was impeccably executed.
Not only is this yet another Exploration Log Where Every One Who Go In Is Meet Their Doom!!, but it contains one of my unforgivable sins of exploration logs: Foundation operatives in the presence of a known or suspected anomaly saying shit like "Oh, it must just be INTERFERENCE" when their equipment acts up. That totally ruins my suspension of disbelief. I understand that there has to be a narrative reason for them to continue in. But the mechanism by which you have them do so just makes them look kinda like they have no idea what they're doing vs. being Mobile Task Force Field Agents. Aaaand then we get inside and the whole thing is run by Carthaginian Mr. Skeltal.
tl;dr - I'm sorry, I can't give this my upvote. :(