All-Loving Hero: Despite his variousissues, David is astonishingly kind and generous to just about everyone, including Eldritch Abominations. Maybe this is why they haven't seriously harmed him yet. One even offered to become his eternal bride and elevate him to godhood in return for his kindness. On the other hand, it may be that they see something special in him... the investigators certainly do.
...especially when you're asking an elder god with very little understanding of humans, let alone human metaphors and euphemisms. When Nancy is summoned, she grants wishes to bystanders, but lethally misinterprets them. A cultist who wants to start a new Columbine shooting hallucinates one (only he's getting shot at instead of doing the shooting) and when he's killed, a lethal bullet wound appears in his head. One wishing that his brain was bigger (smarter) has his head swell to a fatally large size. One wishes for some killer sex, and gets what she asked for, if not what she wanted.
Dave: I wish someone gave a crap about me for once.
Narla hires a ride in exchange for "anything you want". The guy wants to never have to worry about bills again, which she considers an easy one. So many lovely interpretations of that...
Bedmate Reveal: On the part of the author to the audience, when David casually tells Shubbie that Nancy kisses differently than she does. This is the first hint that David and Nancy's romance has progressed that far.
Cute Monster Girl: The Sleeper of N'kai, the Shoggoth, and Shubbie, the "default" form of Shub-Niggurath, "The Black Goat Of The Woods With A Thousand Young" (also Big Beautiful Woman and mom — she has the right figure for what she is.note the "thousand young" part, not the "black goat" part. No malicious intent or insult towards the physique of the average goat is intended)
Dark Is Not Evil: Despite what they are, most of the Lovecraftian entities really seem to be more curious about how humans act than interested in eating them. Nancy herself is fairly nice, deciding to help Dave rather than kill him in order to study his desire to be loved. The Sleeper is literally enamored of Dave for being kind to frogs and the forest. Shubbie seems genuinely amused by/interested in Dave and his relationship with Nancy. The only exception to this (so far) is the Shoggoth, and she seems to be more of a wild animal that needs to be trained than malicious.
Everybody's Dead, Dave: Nancy kills several cultists by misgranting their wishes and sacrifices the rest for power to grant Dave's wish, leaving him the only person left alive in the entire dorm. (And he's named appropriately for this trope.)
Evil Is Not a Toy: Unless all of the cultists had a death wish, summoning Nancy really didn't work out well for them. Some of them didn't even get a wish since Nancy sacrificed them so she could grant Dave's wish instead.
Even more so, he not only predicted that it would either be arson or a gas leak, but also what each possibility meant; "arson" would have meant the architects of the cover-up could get local police in on the hunt, whereas "gas leak" means that they either can't work with the police or don't want to confront him.
He's right on both counts; Delta Green doesn't have government support and is hesitant to confront a "priest" of his "power". Delta Green is right as well - they're just unaware of the exact nature of his "power".
Gender Flip: Narla is of course one of the many Masks of the Crawling Chaos, although that's par for the course really. For those who didn't immediately catch it though, the Sleeper is none other than Tsathoggua.
Gone Horribly Wrong: All of the wishes Nancy granted turned out badly. Time will tell whether or not Dave's wish will follow suit. Although, given that he wished for someone to give a crap about him, one could argue that have that someone be an Eldritch Abomination already counts as going wrong.
Heart Is an Awesome Power: Played absolutely and literally straight. Dave has such good luck with Eldritch Abominations due to his inhumanly intense empathy; this tends to confuse and intrigue them enough for them to not immediately eat his head, and by the time that passes, they're smitten. Unfortunately, it's useless in interacting with other humans, as they use it as an excuse to treat him as a doormat.
This also allows him to just roll with things that would cause others in the Cthulhu Mythos to go stark raving mad.
Human Sacrifice: The cultists have a girl who's already had her arms severed. A bloody knife and Nancy actually appearing pretty much confirm that this went all the way.
Humans Are Special: According to the Mi-go. They're interested in us due to our ability to make leaps of logic, thinking of three without needing to think of two, as well as our incredible rate of development.
On the other hand, the author has said on his blog that it's going to have "a Lovecraft ending." This might mean an optimistic one like The Dunwich Horror or the good ending of Eversion, or it might mean a typical one with Dave and/or a bunch of other humans winding up dead/insane/transmogrified.(Besides, did he say who gets the Lovecraftian ending?) If so, the warm-and-fuzzy-ish beginning just makes things worse. Since it's based on Delta Green, Earth is still doomed, but Dave and friends might not go mad, suicidal or primordial either.
I have a poster. It's called "Pale Blue Dot," and it's got a passage by Sagan on it, and in reading it again, something profound struck me. Lovecraft's horror hinges on the idea that the universe just doesn't care about us. It was not made special. We are not even a footnote in the universe's history. At least, that's how Lovecraft saw it. This was a terrible notion in the 1930s, the most profound source of absolute horror that could be dredged up from the human consciousness and pushed out into a rainy Rhode Island street. Now we hand posters of it on our walls and post rambling, inane blog entries about it like it's the behavior of a new celebrity couple. Cosmic horror isn't scary any more. What was once the great fear of the age is now a joke. Not only that, we're about to start CREATING stars and universes ourselves. We're doing 1930s magic, but we're doing it better than the terrible things in his stories could do it. That's what's funny. That's why we giggle. We all know it, somewhere, subconsciously.
The Stoic: David. His Brown Note reaction to the Eldritch Abominations he's seeing everywhere now is Dissociative disorder — i.e., he's going to be as stoic as he can be...until his insanity finally catches up with him.
Straight Man: The Mi-Go think like computers, and have no capacity for humor or imagination. They make for the perfect straight man.
Narla Hotep, according to the author's Deviant Art gallery.
Unwanted Harem: The author has hinted at this. David seems to be accruing one made entirely of Eldritch Abominations. It's not really there yet, but some chapter names and Thaxton's deviantART gallery give us a peek at what's coming.