SCP Foundation

I won't do a line by line, but some general ideas

Show previous SCP Containment Procedures

First, capitalize. Second, just cross it out. Don't collapse.

re ██% of human

so they share 999%?

case, see Addendum….

put a period. In fact, much of your comma usage is incorrect. Throw it through grammarly. That may help alot. My generally advice is "If you do not need a comma, do not use it."

(see addendum A)

Capitalize Addendum

Kaew Amelin: It is no bother, I hope your trip was pleasant.

Smithe: It was no bother. I would like to ask you some questions, if you wouldn't mind answering them.

Awkward phrasing. In fact, a decent amount of the dialogue is a bit awkward.

I think it has a lot of potential, but it so far seems to be a bit of a "thing that does x" draft. Add a bit more substance, maybe more of a background to it. Why should we care? So these people were cursed, and now the dead kill. So what? That is what you have to answer.

In the event that the creation of an SCP-XXXX-1 instance is inevitable

"Cannot be prevented" would probably make more sense here.

Currently, two SCP-XXXX entites are contained at Site-██, in standard hazardous animal containment cells.

Why would you hold two guys in animal containment cells?

with a population numbering (at last count) 166 individuals.

The Foundation would probably specify when the last count was, to avoid confusion.

The village is entirely cut off from surrounding villages.

How is it cut off? Is it a matter of terrain, or is the Foundation specifically trying to isolate them?

The SCP-XXXX population is notably atheist, however interviews suggest this was not always the case, see Addendum XXXX/C for further information.

Replace "atheist" with "atheistic" and the reference to the addendum should probably be in parentheses. Also, the "interviews suggest…" bit clashes with the tone. I would recommend something like "although interviews suggest this is a recent development".

at which point they undergo a massive change in morphology

"Massive" is a bit too hyperbolic for me to take seriously in an SCP article.

Show previous description

I would cut this part altogether. It doesn't really give any new information about the anomaly, and while it does make sense that the Foundation would keep a backup of old article versions, it doesn't need to be included with the main article.

Addendum XXXX/A:

I would cut this too. They turn into monsters when they die. We get it. We don't need the obituary for every single one.

Addendum XXXX/B:

Same thing for this one. Not every SCP needs to have a discovery log unless it adds to the narrative in some way, which this doesn't.

The interview was conducted in Lao, and has been translated.

Kind of a nitpick, but if this tribe had been isolated for a long time, they probably wouldn't speak Lao. They would have their own language.

nunankansiaalapracao

Firstly, this should be capitalized. Second, I can't take this name seriously. It looks like you plugged "flesh sacrifice god" into google translate. I don't even know how I would begin to pronounce this.

Also, didn't you say this tribe was atheistic?

Addendum XXXX/D:

I don't really see the point of this one either. You are describing a specific individual. If these are common physical features, they should be in the description.

Subject possesses 10% higher upper body strength and 20% higher lower body strength than that expected for an individual with similar levels of activity.

Expressing strength in terms of percentages is probably not ideal.

Ultimately, I didn't find this to be very engaging. The concept runs very close to Shadow Over Innsmouth, but it doesn't go anywhere interesting to differentiate itself, and as it is it's bogged down by a lot of extraneous information. I would recommend fleshing out the concept a bit more before continuing.