Overall:
This was a pretty fun read. The mental image of a bunch of demonic creatures worshiping this regular guy with complete faith is just funny to me. That being said, it felt like the tone and narrative took a turn towards the second half. While the rest of the article is filled with rather funny imagery and ideas, the log detailing the sorrowful and heartfelt apology from the the green demon felt out of place. It may just be me, but I couldn't tell if the scene was meant to be humorous, with this demon crying/drooling out of his eye-mouths, or actually genuine.
For your main character, he's an almost unbelievably chill guy. I mean, he's taken in by a secret organization, then abducted by demons, and he still doesn't seem phased. It's almost to the point where it breaks the suspension of disbelief and moves into a poorly written character, and I can't decide if that's the funnier way to go or if it would be funnier to make him have overdramatic/realistic reactions to everything happening to him.
Specific:
Less frequently, the message will thank SCP-XXXX for answering one of the previous requests.1
I don't really see a reason to put the rather important information that Mathews hasn't been able to fulfill any of the requests in a footnote. It's not supplementary or to help with defining an obscure term, so it should just be tacked on to the end of the sentence.
Three exsanguinated Canadian geese.3
The footnote should be after exsanguinated instead of geese.
Incident Report 18/02/21
This report could be broken up into two or three, as it describes events that happen on different occasions and that don't all relate to the demons taking Mathews.
Watts: No, I heard you the first time. It's just…. wha..?
Funny, but Watts is a doctor and he sounds like he's a teenager or in a sitcom here. Just feels a little unprofessional.
The entity negotiated an agreement with the Foundation, on the terms that SCP-XXXX would remain in the custody of the entities responsible for its capture,4
Knowing that GoI-667 are the entities is another piece of rather important information that's left behind a footnote.
Maybe. The point is, I am truly, deeply sorry for any harm my actions may have caused, and I hope we can come to an understanding someday.
As I mentioned earlier, it a little hard to tell if this scene is actually trying to be heartfelt or not. If it is trying to be heartfelt, it doesn't really blend with the rest of the rest of the article's tone, so I'd recommend leaving it out. If it's trying to be funny, I'd just exaggerate it, cut back on the heartfelt words, and shorten it to get that idea across.
Three days later, SCP-XXXX-A was seen by an undercover Foundation staff member in a crowded food court in Vatican City, speaking on the phone to an unknown individual. Civilians in the area did not seem to acknowledge SCP-XXXX-A's inhuman appearance.
This scene doesn't really make sense. How could the Foundation agent see his true form when nobody else did? It is because they were also around XXXX at some point? In any case, instead of having an agent randomly see them on the street, maybe the Foundation sends a camera drone to XXXX so they can use it to further observe -A, which is how they hear this conversation.
Advice:
Narrative wise, I like the short, humorous story you've written here. There's not really any need for a conclusion since there aren't any serious themes or plot lines to be resolved. I'd just recommend fixing the minor things I mentioned above.
As for an alternative and more unique title, I'm not great with names, but maybe something like "The Reluctant God/Deity"? Or maybe something serious sounding that contrasts with the actual article, like "The Demon God / The God of Demons"?